Bản dịch tiếng Việt trang info của coreutils

Bn dch ca coreutils.info

T SuSE 9.2 Bt u dch: 11-11-2006 Tp tin: coreutils.info, Nt: nh, Tip theo: Gii thiu, Ln: (dir) Coreutils GNU ************* S tay ny cho t liu phin bn 5.2.1 ca cc tin ch li (core utilities) GNU, m gm cc chng trnh chun cho s thao tc vn bn v tp tin. Copyright (C) 1994, 1995, 1996, 2000, 2001, 2002, 2003, 2004 Free Software Foundation, Inc. (nd: Bn quyn (C) 1994, ..., 2004 Lin hip T chc Phn mm T do) S cho php c ban chp, phn phi v/ hay thay i ti liu ny di cc iu khon ca Bn cp php Ti liu T do GNU (GNU Free Documentation License), Phin bn 1.1 hay bt k phin bn mi hn no m c cng b bi T chc Phn mm T do; vi khng c cc Phn Bt bin no, vi khng c cc Vn bn Ba Mt trc (Front-Cover Texts) no, v vi khng c cc Vn bn Ba Mt sau (Back-Cover Texts) no. Mt bn sao ca bn cp php c gm vo phn m c ghi u "GNU Free Documentation License" (Bn cp php Ti liu T do GNU). * Menu: * Gii thiu:: Caveats, tng quan v cc tc gi. * Cc ty chn chung:: Cc ty chn chung. * D liu xut/ u ra ca ton b cc tp tin:: cat tac nl od * nh dng ni dung tp tin:: fmt pr fold * D liu xut ca cc phn ca cc tp tin:: head tail split csplit * Tm tt ha cc tp tin:: wc sum cksum md5sum * Lm cc php ton (Operating) trn cc tp tin c sp xp:: sort uniq comm ptx tsort * Lm cc php ton trn cc trng trong vng mt dng:: cut paste join * Lm cc php ton trn cc k t:: tr expand unexpand * Lit k th mc:: ls dir vdir d v dircolors * Cc hot ng c bn:: cp dd install mv rm shred * Cc kiu tp tin c bit:: ln mkdir rmdir mkfifo mknod * Thay i cc thuc tnh tp tin:: chgrp chmod chown touch * Cch dng a (Disk usage):: df du stat syncTrang 1/369


* In vn bn:: echo printf yes * Cc iu kin:: false true test expr * Ti nh hng:: tee * Thao tc tn tp tin:: dirname basename pathchk * Lm vic vi ng cnh (Working context):: pwd stty printenv tty * Thng tin ngi dng:: id logname whoami groups users who * Ng cnh h thng (System context):: date uname hostname * Triu gi lnh c thay i:: chroot env nice nohup su * iu khin tin trnh:: kill * Tr hon:: sleep * Cc php ton s (Numeric operations):: factor seq * Nhng s cp php/ cc quyn/ cc quyn thao tc tp tin (File permissions):: Cc ch truy cp. * Cc nh dng nhp liu ngy thng:: Ch r cc chui ngy thng. * M hp cng c phn mm (software toolbox):: Trit l v cc cng c phn mm (The software tools philosophy). * Bn cp php Ti liu T do GNU:: Bn cp php cho ti liu ny. * Bng ch mc:: Bng ch mc chung. --- Lit k nt chi tit --Cc ty chn chung * Tnh trng thot:: Ch ra s thnh cng hay tht bi ca chng trnh. * Cc ty chn d phng (Backup):: Cc ty chn d phng * Kch c khi (Block size):: Kch c khi * Th mc mc tiu:: Th mc mc tiu * Trailing slashes:: Trailing slashes * i theo cc lin kt tng trng (symlinks):: i theo cc lin kt tng trng n cc th mc * Treating / specially:: Treating / specially * S hp cc tiu chun (Standards conformance):: S hp cc tiu chun S xut liu/ d liu xut/ u ra (output) ca ton b cc tp tin * triu gi cat:: * triu gi tac:: * triu gi nl:: Chp ni (Concatenate) v vit cc tp tin. Chp ni v vit cc tp tin ngc chiu (in reverse). nh s cc dng v vit cc tp tin.Trang 2/369


* triu gi od::

Vit cc tp tin theo cc nh dng bt phn hay khc.

nh dng ni dung tp tin * triu gi fmt:: * triu gi pr:: * triu gi fold:: Ti nh dng vn bn on vn. nh s trang hay chia ct (columnate) cc tp tin cho vic in. Gi (Wrap) cc dng d liu nhp va vo chiu rng c ch r.

Output ca cc phn ca cc tp tin * triu gi head:: * triu gi tail:: * triu gi split:: * triu gi csplit:: determined pieces). Tm tt ha cc tp tin * triu gi wc:: * triu gi sum:: * triu gi cksum:: byte counts). * triu gi md5sum:: In cc s m (counts) newline, t (word) v byte. In cc s m c s kim tra (checksum) v khi. In cc s m c s kim tra CRC v byte (Printing CRC checksum and In hay kim tra message-digests. Xut liu (Output) phn u tin ca cc tp tin. Xut liu phn cui cng ca cc tp tin. Chia tch mt tp tin thnh cc mnh kch c c nh. Chia tch mt tp tin thnh cc mnh c xc nh bi ng cnh (context-

Lm cc php ton trn cc tp tin c sp xp * triu gi sort:: * triu gi uniq:: * triu gi comm:: line by line). * triu gi ptx:: * triu gi tsort:: Sp xp cc tp tin vn bn. c nht ha (Uniquify) cc tp tin. So snh hai tp tin c sp xp dng vi dng (Compare two sorted files Sinh mt bng ch mc c hon v (permuted) ca ni dung tp tin. Sp xp kiu t-p hc (Topological sort).

`ptx': Sinh cc ch mc (indexes) c hon v * Cc ty chn chung trong ptx:: Cc ty chn m nh hng n s hnh x chng trnh chung. * S chn b k t (Charset) trong ptx:: Cc lu v b k t c s (Underlying character setTrang 3/369


considerations). * S x l d liu nhp trong ptx:: S nhp liu cc trng, cc ng cnh v s chn t kha (Input fields, contexts, and keyword selection). * nh dng d liu xut trong ptx:: Cc kiu nh dng d liu xut, v vic nh c cc trng. * Tnh tng thch trong ptx:: Nhng s m rng (extensions) GNU n (to) `ptx' Lm cc php ton trn cc trng trong vng mt dng * Triu gi cut:: * Triu gi paste:: * Triu gi join:: In cc phn c chn ca cc dng. Ha trn cc dng ca cc tp tin. Chp ni cc dng trn mt trng chung.

Lm cc php ton trn cc k t * Triu gi tr:: Dch (Translate), chen/ sit (squeeze), v/ hay xa cc k t. * Triu gi expand:: i cc du tab thnh cc du cch. * Triu gi unexpand:: i cc du cch thnh cc du tab. `tr': Dch (Translate), chen/ sit (squeeze), v/ hay xa cc k t * Cc b k t:: Ch r cc b cc k t. * Dch:: i mt b cc k t thnh mt ci khc. * Vic chen (Squeezing):: Vic chen (Squeezing) cc ch lp (repeats) v vic xa. * Cc cnh bo trong tr:: Cc thng bo cnh bo. Lit k th mc * triu gi ls:: Lit k ni dung th mc * triu gi dir:: Lit k ngn gn ni dung th mc * triu gi vdir:: Lit k lm li ni dung th mc * triu gi dircolors:: Thit lp mu sc cho `ls' `ls': Lit k ni dung th mc * Which files are listed:: Cc tp tin no c lit k * What information is listed:: Thng tin g c lit k * Sorting the output:: Sp xp d liu xutTrang 4/369


* More details about version sort:: Nhiu chi tit hn v version sort * General output formatting:: Vic nh dng d liu xut chung * Formatting the file names:: Vic nh dng cc tn tp tin Cc hot ng c bn * triu gi cp:: * triu gi dd:: * triu gi install:: * triu gi mv:: * triu gi rm:: * triu gi shred:: Chp cc tp tin v cc th mc Chuyn i v chp mt tp tin Chp cc tp tin v t nh cc thuc tnh Di chuyn (t tn li) cc tp tin Ly i cc tp tin hay cc th mc Ly i cc tp tin mt cch an ninh hn

Cc kiu tp tin c bit * triu gi link:: gi h thng link?) * triu gi ln:: * triu gi mkdir:: * triu gi mkfifo:: tn (named pipes)) * triu gi mknod:: * triu gi readlink:: * triu gi rmdir:: * triu gi unlink:: unlink?) Lm ra mt lin kt cng (hard link) qua link syscall (nd: link system call - li Lm ra cc lin kt gia cc tp tin Lm ra cc th mc Lm ra cc FIFO (nd: first in first out - vo trc ra trc?) (cc ng dn c Lm ra cc tp tin khi hay k t c bit In referent ca mt lin kt tng trng Ly i cc th mc rng Ly i cc tp tin qua unlink syscall (nd: unlink system call - li gi h thng

Thay i cc thuc tnh tp tin * triu gi chown:: * triu gi chgrp:: * triu gi chmod:: * triu gi touch:: S dng a (Disk usage) * triu gi df:: Bo co s dng khng gian a (ca) h tp tin (filesystem disk space usage)Trang 5/369

Thay i s hu ch v nhm ca tp tin Thay i quyn s hu nhm Thay i cc quyn truy cp (access permissions) Thay i cc con du/ tem thi gian (timestamps) ca tp tin


* triu gi du:: * triu gi stat:: * triu gi sync:: In vn bn * triu gi echo:: * triu gi printf:: * triu gi yes:: Cc iu kin * triu gi false:: * triu gi true:: * triu gi test:: * triu gi expr::

c lng s dng khng gian ca tp tin (file space usage) Bo co tnh trng tp tin hay h tp tin ng b ha cc d liu trn a vi b nh

In mt dng vn bn nh dng v in cc d liu In mt chui cho n khi b lm gin on

Khng lm g c, mt cch tht bi (Do nothing, unsuccessfully) Khng lm g c, mt cch thnh cng (Do nothing, successfully) Kim tra cc loi tp tin v so snh cc gi tr Lng gi (Evaluate) cc biu thc

`test': Kim tra cc loi tp tin v so snh cc gi tr * File type tests:: Cc trc nghim loi tp tin * Access permission tests:: Cc trc nghim quyn truy cp (Access permission) * File characteristic tests:: Cc trc nghim c trng tp tin (File characteristic) * String tests:: Cc trc nghim chui * Numeric tests:: Cc trc nghim s èxpr': Lng gi biu thc * String expressions:: (Cc biu thc chui) + : match substr index length * Numeric expressions:: (Cc biu thc s) + - * / % * Relations for expr:: (Cc quan h cho biu thc) | & < = > * Examples of expr:: (Cc v d cho biu thc) Cc v d ca vic dng èxpr' Ti nh hng * tee invocation:: Thao tc tn tp tinTrang 6/369

(triu gi tee) Ti nh hng d liu xut n nhiu tp tin


* basename invocation:: (triu gi basename) Lt/ bc/ tc (Strip) th mc v hu t/ tip v ng (suffix) khi mt tn tp tin * dirname invocation:: (triu gi dirname) Tc hu t khng phi th mc khi mt tn tp tin * pathchk invocation:: (triu gi pathchk) Kim tra tnh d mang (portability) ca tn tp tin Lm vic vi ng cnh (Working context) * pwd invocation:: * stty invocation:: characteristics) * printenv invocation:: * tty invocation:: input) (triu gi pwd) In th mc lm vic (Print working directory) (triu gi stty) In hay thay i cc c trng thit b u cui (terminal (triu gi printenv) In tt c hay vi bin mi trng (triu gi tty) In tn tp tin ca thit b u cui trn u ra chun (standard

`stty': In hay thay i cc c trng thit b u cui * Control:: * Input:: * Output:: * Local:: * Combination:: * Characters:: * Special:: Thng tin ngi dng * id invocation:: * logname invocation:: * whoami invocation:: * groups invocation:: * users invocation:: * who invocation:: (triu gi id) In uid v gid thc v hu hiu (effective) (triu gi logname) In tn ng nhp (login) hin ti (triu gi ) Print effective user id (triu gi ) Print group names a user is in (triu gi ) Print login names of users currently logged in (triu gi ) Print who is currently logged in (iu khin) Cc t nh iu khin (u vo/ d liu nhp/ ni nhp liu) Cc t nh nhp liu (u ra/ d liu xut/ ni xut liu) Cc t nh xut liu (Cc b/ a phng) Cc t nh cc b (T hp) Cc t nh t hp (Cc k t) Cc k t c bit (c bit) Cc t nh c bit

(nd: font ch: chui vn bn ting Anh "The quick brown fox jumps over the lazy dog" c dng kim tra b mu ch ting Anh v n c cc ch ci ting Anh (Khng bit ai l ngi u tin ngh ra n?). Vi ting Vit th phi dng chui khc ch khng th my mc dch li chui ny khi Vit haTrang 7/369


HH) Ng cnh h thng * date invocation:: * uname invocation:: (triu gi date) In hay t nh ngy thng v thi gian h thng (triu gi uname) In thng tin h thng

`date': In hay t nh ngy thng v thi gian h thng * Time directives:: * Date directives:: * Literal directives:: * Padding:: * Setting the time:: * Options for date:: * Examples of date:: Cc ch dn thi gian Cc ch dn ngy thng Cc ch dn ngha en/ bng ch (Literal directives) Vic nhi m t nh thi gian Cc ty chn cho `date' Cc v d ca `date'

Triu gi lnh c bin i/ bin ci (Modified) * chroot invocation:: (triu gi chroot) Chy mt lnh vi mt th mc khc gc (a different root directory) * env invocation:: (triu gi env) Chy mt lnh trong mt mi trng c bin ci * nice invocation:: (triu gi nice) Chy mt lnh vi tnh u tin lp thi biu c bin ci (modified scheduling priority) * nohup invocation:: (triu gi nohup) Chy mt lnh m min khi nhng s treo (Run a command immune to hangups) * su invocation:: (triu gi su) Chy mt lnh vi id ngi dng v nhm thay th iu khin tin trnh * kill invocation:: Tr hon * sleep invocation:: Cc php ton sTrang 8/369

(triu gi kill) Gi mt tn hiu n cc tin trnh.

(triu gi sleep) Tr hon trong mt thi gian c ch r


* factor invocation:: * seq invocation::

(triu gi factor) In cc tha s chnh (prime factors) (triu gi seq) In cc trnh t (sequences) s

Nhng s cp php tp tin (File permissions) * Mode Structure:: * Symbolic Modes:: * Numeric Modes:: (Cu trc Ch ) Cu trc ca cc cp php tp tin (Cc ch Tng trng) S i din cc cp php gi nh (Cc ch S) Cc cp php nh cc s bt phn

Cc nh dng d liu nhp ngy thng * General date syntax: C php ngy thng chung * Calendar date items: Cc mc ngy thng ca lch * Time of day items: Cc mc thi gian ca/ trong ngy * Time zone items: Cc mc mi gi (Time zone) * Day of week items: Cc mc ngy ca/ trong tun (Day of week) * Relative items in date strings: Cc mc tng i trong cc chui ngy thng * Pure numbers in date strings: Cc s n thun trong cc chui ngy thng * Authors of getdate: Cc tc gi ca getdate M hp cng c phn mm * Toolbox introduction:: Gii thiu hp cng c * I/O redirection:: S ti nh hng nhp/ xut * The who command:: Lnh `who' * The cut command:: Lnh `cut' * The sort command:: Lnh `sort' * The uniq command:: Lnh ùniq' * Putting the tools together:: t cc cng c cng vi nhau Bn cp php Ti liu T do GNU * How to use this License for your documents:: (Cch dng Bn cp php ny cho cc ti liu ca bn) File: coreutils.info, Node: Introduction, Next: Common options, Prev: Top, Up: Top

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1 Gii thiu ************** S tay ny l mt tc phm/ cng vic (work) ang tip din: nhiu phn khng c gii thch cc khi nim c bn theo mt cch m thch hp cho nhng ngi nhp mn (novices). Do , nu bn quan tm, xin vui lng tr nn dnh lu vo (get involved in) vic ci thin s tay ny. Ton cng ng GNU s hng li. Cc tin ch GNU m c ghi ti liu y hu ht tng thch vi chun POSIX. Xin vui lng bo co cc li n . Hy nh bao gm s ca phin bn, cu trc my, cc tp tin u vo v bt k thng tin khc no m c cn ti to li: s nhp liu ca bn, bn mong i g, bn c c g, v v sao n sai. Cc diff c hoan nghnh, nhng xin vui lng cng bao gm mt m t ca vn , do ci ny i khi kh suy lun ra. *Note Bugs: (gcc)Bugs (Cc li). S tay ny bt ngun nguyn t cc trang s tay Unix trong cc bn phn phi, m c vit bi David MacKenzie v c cp nht bi Jim Meyering. Nhng g bn ang c by gi l ti liu c thm quyn/ c cn c ch xc (authoritative) cho cc tin ch ny; cc trang s tay khng cn ang c duy tr na. Trang s tay `fmt' nguyn thy c vit bi Ross Paterson. Franc,ois Pinard lm s chuyn i ban u thnh nh dng Texinfo. Karl Berry lm vic ghi ch mc (indexing), mt t s ti t chc, v vic bin tp cc kt qu. Brian Youmans ca i ng vn phng ca T chc Phn mm T do (Free Software Foundation office staff) kt hp cc s tay cho cc tin ch vn bn (textutils), cc tin ch tp tin (fileutils), v cc tin ch sh (sh-utils) sinh ra s tay nhiu mc hin ti. Richard Stallman ng gp nhng s hiu thu (insights) v gi thng l ca ng/ anh vo qu trnh tng th. File: coreutils.info, Node: Common options, Next: Output of entire files, Prev: Introduction, Up: Top 2 Cc ty chn chung **************** Cc ty chn no l c sn trong tt c cc chng trnh ny. Hn l vic vit cc m t ging ht cho mi trong s cc chng trnh, chng c m t y. (Trong thc t, mi chng trnh GNU chp nhn (hay nn chp nhn) cc ty chn ny.) Bnh thng, cc ty chn v cc ton hng (operands) c th xut hin theo bt k th t no, v cc chng trnh hnh ng nh th tt c cc ty chn xut hin pha trc bt k cc ton hng no. V d, `sort -r passwd -t :' hnh ng nh `sort -r -t : passwd' (nd: "passwd"=="mt_khu"?), do `:' l mtTrang 10/369


tham s ty chn (option-argument) ca `-t'. Tuy nhin, nu bin mi trng `POSIXLY_CORRECT' (nd: chnh xc theo kiu posix?) c t nh, cc ty chn phi xut hin trc cc ton hng, tr khi c ch r khc i (Tr khi (?) otherwise specified) cho mt lnh c bit (particular). (nd: V d ny hi kh hiu vi ngi nhp mn v h cha hiu "tham s ty chn" v "bin mi trng" l g) Vi trong s cc chng trnh ny nhn ra/ tha nhn (recognize) cc ty chn `--help' v `--version' ch khi mt trong s chng l tham s dng lnh duy nht. `--help' In mt thng bo s dng (usage message) m lit k tt c cc ty chn c sn ri thot thnh cng. `--version' In s ca phin bn ri thot thnh cng. `--' (nd: hai du "-") nh ranh gii/ Hn nh (Delimit) danh sch ty chn. Cc tham s sau , nu c bt k ci no, c x l nh cc ton hng thm ch nu chng bt u bng `-'. V d, `sort -- -r' c t tp tin c tn `-r'.

Mt `-' n l/ mt mnh (single) khng thc s l mt ty chn, d n trng ging mt ci (nh th) (though it looks like one). N i din cho s nhp liu/ d liu nhp chun, hay cho d liu xut chun nu ci l r rng vi ng cnh (if that is clear from the context), v n c th c dng nh mt ton hng hay nh mt tham s- ty chn (hay l "ty chn- tham s"? ngha l mt ci g mang c hai tnh cht "ty chn" v "tham s"? Cn gii thch thm) (option-argument). V d, `sort -o - -' xut liu n u ra chun (outputs to standard output) v c t u vo chun (reads from standard input), v tng ng vi `sort' n thun (plain). Tr khi c ch r khc i, `-' c th xut hin trong bt k ng cnh no m i hi mt tn tp tin. (nd: t "context" kh l m h, c dch ba l "ng cnh")

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* Menu: * Exit status:: (Tnh trng thot) Ch ra s thnh cng hay tht bi ca chng trnh. * Backup options:: (Cc ty chn (lu) d phng) -b -S -V, trong vi chng trnh. * Block size:: (Kch c khi) BLOCK_SIZE v --block-size, trong vi chng trnh. * Target directory:: (Th mc mc tiu) --target-directory, trong vi chng trnh. * Trailing slashes:: (Cc du vch xin/ du xuyt i cui) --strip-trailing-slashes, trong vi chng trnh. * Traversing symlinks:: (i theo cc lin kt tng trng) -H, -L, hay -P, trong vi chng trnh. * Treating / specially:: --preserve-root v --no-preserve-root. * Standards conformance:: (S tun theo cc chun) S tun theo chun POSIX. File: coreutils.info, Node: Exit status, Next: Backup options, Up: Common options 2.1 Tnh trng thot =============== Gn nh mi s triu gi lnh sinh ra mt "tnh trng thot" (exit status) s nguyn m c th c dng thay i cch cc chng trnh khc lm vic. Cho i a s cc lnh (For the vast majority of commands), mt tnh trng thot s khng ch ra s thnh cng. S tht bi c ch ra bi mt gi tr khc khng--tiu biu l `1', d n c th khc bit trn cc h nn t dng do POSIX ch i hi rng n l khc khng (requires only that it be nonzero). Tuy nhin, vi trong s cc chng trnh m c ghi ti liu y sinh cc gi tr tnh trng thot khc v mt vi ngha khc c kt hp vi cc gi tr `0' v `1'. y l vi trong s cc ngoi l: `chroot', ènv', èxpr', `nice', `nohup', `printenv', `sort', `su', `test', `tty'. File: coreutils.info, Node: Backup options, Next: Block size, Prev: Exit status, Up: Common options 2.2 Cc ty chn d phng ================== Vi chng trnh GNU (t nht l `cp', ìnstall', `ln' v `mv') mt cch ty chn lm ra cc bn d phng (backups) ca cc tp tin trc khi vit cc phin bn mi. Cc ty chn ny iu khin cc chi tit ca nhng s lu d phng (backups) ny. Cc ty chn cng c cp ngn gn trong cc m t ca cc chng trnh c bit.

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`-b' `--backup[=PHNG_PHP]' Lm ra mt bn d phng ca mi tp tin m nu khng l ra b vit hay b ly i (file that would otherwise be overwritten or removed). Khng c ty chn ny, cc phin bn nguyn thy b hy. Hy dng PHNG_PHP xc nh (determine) kiu/ loi (type) ca cc bn d phng cn lm ra. Khi ty chn ny c dng nhng PHNG_PHP khng c ch r th gi tr ca bin mi trng `VERSION_CONTROL' (nd: iu khin phin bn) c dng. V nu `VERSION_CONTROL' khng c t nh, loi d phng mc nh (default backup type) l èxisting' (hin hu). Hy ch rng dng ngn ca ty chn ny, `-b', khng chp nhn bt k tham s no. Vic dng `b' l tng ng vi vic dng `--backup=existing'. Ty chn ny p ng vi bin Emacs `version-control'; cc gi tr cho METHOD (phng php) l ging nh nhng ci m c dng trong Emacs. Ty chn ny cng chp nhn nhiu tn m t (descriptive names) hn. Cc METHOD c hiu lc l (cc t vit tt (abbreviations) c nht c chp nhn): `none' (khng c g) òff' (tt) Khng bao gi lm ra cc bn d phng (Never make backups). `numbered' (c nh s) `t' Lun lm ra cc bn d phng c nh s (make numbered backups). èxisting' (hin hu) `nil' (khng) Lm ra cc bn d phng c nh s ca cc tp tin m c chng ri, cc bn d phng n gin ca nhng ci cn li. `simple' (n gin) `never' (khng bao gi) Lun lm ra cc bn d phng n gin. Xin vui lng ch l `never' khng c b nhm ln vi (is not to be confused with) `none'.

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`-S HU_T' `--suffix=HU_T' Chp ghp HU_T vo mi tp tin d phng m c lm ra vi `-b'. Nu ty chn ny khng c ch r, gi tr ca bin mi trng `SIMPLE_BACKUP_SUFFIX' (hu t d phng n gin) c dng. V nu `SIMPLE_BACKUP_SUFFIX' khng c t nh, ci mc nh l `~', ch nh/ ng nh (just as) trong Emacs. `--version-control=PHNG_PHP' Ty chn ny li thi v s b ly i trong mt bn pht hnh tng lai. N c thay th bng `-backup'.

File: coreutils.info, Node: Block size, Next: Target directory, Prev: Backup options, Up: Common options 2.3 Kch c khi ============== Vi chng trnh GNU (t nht l `df', `du' v `ls') hin th cc kch c theo "khi" (blocks). Bn c th iu chnh kch c khi v phng php hin th lm cho cc kch c d c hn. Kch c khi m c dng cho s hin th l c lp vi bt k kch c khi h tp tin no. Cc s m khi phn s (Fractional block counts) c lm trn ln n s nguyn gn nht. Kch c khi mc nh c chn bng cch ln lt kim tra cc bin mi trng sau (The default block size is chosen by examining the following environment variables in turn); ci u tin m c t nh xc nh kch c khi. `DF_BLOCK_SIZE' (kch c khi mc nh (default)) Ci ny ch r kch c khi mc nh cho lnh `df'. Tng t, `DU_BLOCK_SIZE' (kch c khi du) ch r ci mc nh cho `du' v `LS_BLOCK_SIZE' (kch c khi ls) cho `ls'. `BLOCK_SIZE' (kch c khi) Ci ny ch r kch c khi mc nh cho tt c ba lnh, nu cc bin mi trng c trng dng lnh trn khng c t nh. `POSIXLY_CORRECT' (chnh xc theo kiu POSIX) Nu khng c cc bin `COMMAND_BLOCK_SIZE' (kch c khi lnh) ln `BLOCK_SIZE' (kchTrang 14/369


c khi) no c t nh, nhng bin ny c t nh, kch c khi mc nh 512.

Nu khng c ci no trong s cc bin mi trng trn c t nh, kch c khi th mc nh hin ti 1024 byte trong hu ht cc ng cnh, nhng s ny c th thay i trong tng lai. Cho cc kch c tp tin `ls', kch c khi mc nh 1 byte. Mt s nh r kch c khi (block size specification) c th l mt s nguyn dng m ch r s cc byte mi khi, hay n c th l `human-readable' (d cho ngi c) hay `si' chn mt nh dng d cho ngi c. Cc s nguyn c th c theo sau bi cc hu t m tng thch v pha trn (upward) vi cc tin t SI (http://www.bipm.fr/enus/3_SI/si-prefixes.html) cho cc bi s thp phn v vi cc tin t IEC 60027-2 cho cc bi s nh phn (http://physics.nist.gov/cuu/Units/binary.html). Vi cc nh dng d cho ngi c, cc kch c xut liu c theo sau bi mt ch ci kch c nh l `M' cho cc megabyte. `BLOCK_SIZE=human-readable' dng cc ly tha (powers) ca 1024; `M' i din cho 1.048.576 byte. `BLOCK_SIZE=si' l tng t, nhng dng cc ly tha ca 1000 v chp ni `B'; `MB' i din cho 1.000.000 byte. Mt s nh r kch c khi m c i trc bi `'' lm cho cc kch c xut liu c hin th vi cc du phn cch hng nghn (thousands separators). Qui c a phng (local) `LC_NUMERIC' (kiu s a phng (local)) ch r du phn cch v vic gp nhm hng nghn (the thousands separator and grouping). V d, theo mt qui c a phng Anh M (American English locale), `--block-size="'1kB"' s lm cho mt kch c 1234000 byte c hin th nh `1,234'. Trong qui c a phng C mc nh (nd: "C" l ngn ng lp trnh?), khng c du phn cch hng nghn no vy mt `'' dn u khng c hiu qu no. (nd: "locale" c ngha gc l "a phng" (?), nhng trong my tnh chng c mt "a phng" no c (ngha l chng c sng sui, ao h, nh th, trng hc, con ngi (i l hng t nhng vt th vt l c thc trong cuc sng thc), v.v... no c), vy "locale" c th c tm dch l "qui c a phng" hay "tp qui c a phng") Mt kch c khi s nguyn c th c theo sau bi mt hu t ch r mt bi s ca kch c . Mt ch ci kch c trn (bare size letter), hay ci m c theo sau bi ìB', ch r mt bi s m dng cc ly tha ca 1024. Mt ch ci kch c m c theo sau bi `B' ch r cc ly tha ca 1000 thay vo . V d, `1M' v `1MiB' tng ng vi `1048576', trong khi `1MB' tng ng vi `1000000'. Mt hu t trn m khng c mt s nguyn i trc hnh ng nh th `1' c chp ni voTrang 15/369


trc (prepended) vy, ngoi tr rng n lm cho mt ch s kch c (size indication) c chp ghp vo d liu xut. V d, `--block-size="kB"' hin th 3000 nh `3kB'. Cc hu t sau c nh ngha. Cc kch c ln nh `1Y' c th b bc b bi my tnh ca bn do cc hn ch (limitations) ca s hc ca n (its arithmetic). `kB' kilobyte: 10^3 = 1000. `k' `K' `KiB' kibibyte: 2^10 = 1024. `K' l c bit: tin t SI l `k' v tin t IEC 60027-2 l `Ki', nhng truyn thng v POSIX dng `k' biu ngha (mean) `KiB'. `MB' megabyte: 10^6 = 1.000.000. `M' `MiB' mebibyte: 2^20 = 1.048.576. `GB' gigabyte: 10^9 = 1.000.000.000. `G' `GiB' gibibyte: 2^30 = 1.073.741.824. `TB' terabyte: 10^12 = 1.000.000.000.000. `T' `TiB' tebibyte: 2^40 = 1.099.511.627.776. `PB'Trang 16/369


petabyte: 10^15 = 1.000.000.000.000.000. `P' `PiB' pebibyte: 2^50 = 1.125.899.906.842.624. ÈB' exabyte: 10^18 = 1.000.000.000.000.000.000. È' ÈiB' exbibyte: 2^60 = 1.152.921.504.606.846.976. `ZB' zettabyte: 10^21 = 1.000.000.000.000.000.000.000 `Z' `ZiB' 2^70 = 1.180.591.620.717.411.303.424. (`Zi' l mt phn m rng (extension) GNU n IEC 60027-2.) `YB' yottabyte: 10^24 = 1.000.000.000.000.000.000.000.000. `Y' `YiB' 2^80 = 1.208.925.819.614.629.174.706.176. (`Yi' l mt phn m rng GNU n IEC 60027-2.) Cc (gi tr) mc nh (defaults) kch c khi c th c ginh quyn bi mt ty chn `--blocksize=KCH_C' tng minh. Ty chn `-k' tng ng vi `--block-size=1K', m l ci mc nh tr khi bin mi trng `POSIXLY_CORRECT' c t nh. Ty chn `-h' hay `--human-readable' tng ng vi `--block-size=human-readable'. Ty chn `--si' tng ng vi `--block-size=si'. File: coreutils.info, Node: Target directory, Next: Trailing slashes, Prev: Block size, Up: Common options 2.4 Th mc mc tiuTrang 17/369


==================== Vi chng trnh GNU (t nht l `cp', ìnstall', `ln' v `mv') cho php bn ch r th mc mc tiu qua ty chn ny: `--target-directory=TH_MC' Ch r ni n TH_MC. Giao din cho hu ht cc chng trnh l rng sau khi x l cc ty chn v mt s hu hn (c th l s khng) cc tham s c v tr c nh (fixed-position arguments), danh sch tham s cn li hoc l c mong i l rng, hoc l mt danh sch cc mc (thng l cc tp tin) m s u c thao tc ging ht nhau. Chng trnh `xargs' c thit k lm vic tt vi qui c ny. Cc lnh trong h `mv' l bt thng theo cch l chng ly mt s bin i cc tham s vi mt dng in hoa- thng/ dng ch/ th cch c bit _phn cui_ (y l th mc mc tiu) (The commands in the `mv'-family are unusual in that they take a variable number of arguments with a special case at the _end_ (namely, the target directory)). iu ny lm cho vic thc hin vi php ton/ hot ng tr nn bt thng (This makes it nontrivial to perform some operations), v.d., "di chuyn tt c cc tp tin t y n ../d/", do `mv * ../d/' c th vt cn (might exhaust) khng gian tham s (argument space), v `ls | xargs ...' khng c mt ng thng thong/ cch r rng (clean way) ch r mt tham s cui cng thm vo cho mi s triu gi lnh ch th (subject command). (N c th c lm bng cch i qua mt lnh h v, nhng iu i hi nhiu lao ng v sc mnh tr c con ngi hn l n nn lm (but that requires more human labor and brain power than it should).) Ty chn `--target-directory' cho php cc chng trnh `cp', ìnstall', `ln' v `mv' c dng tin li vi `xargs'. V d, bn c th di chuyn cc tp tin t th mc hin ti n mt th mc anh ch em (sibling directory), `d' nh th ny: (Tuy nhin, iu ny khng di chuyn cc tp tin m cc tn ca chng bt u bng `.'.) ls |xargs mv --target-directory=../d (nd: Th d ny kh phc tp vi ngi mi hc) Nu bn dng chng trnh `find' GNU, bn c th di chuyn _tt c_ cc tp tin vi lnh ny: find . -mindepth 1 -maxdepth 1 \ | xargs mv --target-directory=../d (nd: du "\" c ngha l g? Xung dng trn dng lnh?)Trang 18/369


Nhng iu s tht bi nu khng c cc tp tin no trong th mc hin ti hay nu bt k tp tin no c mt tn m cha mt k t newline (nd: "dng mi"?). V d sau ly i cc hn ch v i hi c `find' GNU ln `xargs' GNU: find . -mindepth 1 -maxdepth 1 -print0 \ | xargs --null --no-run-if-empty \ mv --target-directory=../d (nd: thc mc v du "\" cng nh trn. Ngi dch nh nguyn v l do thn trng) File: coreutils.info, Node: Trailing slashes, Next: Traversing symlinks, Prev: Target directory, Up: Common options 2.5 Cc slashes (vt chm??, hay "du vch cho xui" ("/")) i cui ==================== Vi chng trnh GNU (t nht l `cp' v `mv') cho php bn ly i bt k cc slash i cui no khi tham s SOURCE (NGUN) trc khi thao tc trn n (operating on it). Ty chn `--strip-trailingslashes' cho php s hnh x ny. iu ny c ch khi mt tham s NGUN c th c mt slash i cui v ch r mt lin kt tng trng n mt th mc. Hon cnh ny (This scenario) trong thc t l kh thng thng do vi h v c th t ng chp ghp mt slash i cui khi thc hin s hon tt tn tp tin trn cc lin kt tng trng nh th. Khng c ty chn ny, `mv', v d th, (qua chc nng/ hm t tn li/ rename ca h thng (via the system's rename function)) phi din dch (interpret) mt slash i cui nh mt yu cu b tham chiu lin kt tng trng (as a request to dereference the symbolic link) v v th phi t tn li (and so must rename) _th mc_ c tham chiu gin tip v khng phi l lin kt tng trng. D vic s hnh x nh th l mc nh c th dng nh l gy ngc nhin, n c i hi bi POSIX v nht qun vi cc phn khc ca chun . (nd: T in StarDict ca Hacao.Office Linux 2.05 khng c nh ngha hp l cho t "slash" nhng c ngha cho t "backslash". nh on m vy :-)) File: coreutils.info, Node: Traversing symlinks, Next: Treating / specially, Prev: Trailing slashes, Up: Common options 2.6 i theo cc lin kt tng trngTrang 19/369


======================= Cc ty chn sau y thay i cch `chown' v `chgrp' i theo mt h thng th bc khi ty chn `-recursive' ( qui) (`-R') cng c ch r. Nu nhiu hn mt trong s cc ty chn sau c ch r, ch c ci cui cng c hiu qu (takes effect). Cc ty chn ny ch r vic x l mt lin kt tng trng n mt th mc l k tha (entails) vic thao tc trn ng lin kt tng trng (on just the symbolic link) hay l trn tt c cc tp tin trong h thng th bc m c gc (rooted) th mc . (nd: T "just" l mt t nguy him v c lc c ngha l "ng", "chnh", c lc c ngha l "ch", "ch c". Nhng ai c nh vit mi cc phn hng dn nh cc trang s tay hay cc ti liu info cn lu trnh cc t nguy him ny.) Cc ty chn ny c lp vi `--dereference' v `--no-dereference' (`-h'), m iu khin vic thay i mt lin kt tng trng hay th tham chiu ca n (whether to modify a symlink or its referent). `-H' Nu `--recursive' (`-R') c ch r v mt tham s dng lnh l mt lin kt tng trng n mt th mc, hy i theo n. `-L' Trong mt traversal qui, hy i theo mi lin kt tng trng n mt th mc m c bt gp. `-P' Khng i theo bt k cc lin kt tng trng no. y l mc nh nu khng c ci no trong s `H', `-L' hay `-P' c ch r.

File: coreutils.info, Node: Treating / specially, Next: Standards conformance, Prev: Traversing symlinks, Up: Common options 2.7 Treating / specially ======================== Cc lnh no c th vn hnh theo kiu ph hoi trn ton b cc h thng th bc. V d, nu mt ngi dng vi cc c quyn thch hp chy nhm `rm -rf / tmp/junk' hay `cd /bin; rm -rf ../', iu c th ly i tt c cc tp tin trn ton b h thng. Do c t (1) s dng hp php nh th cho mt lnh nh th, `rm' GNU cung cp ty chn `--preserve-root' (bo tn gc) lm n, vy `rm' t chiTrang 20/369


vn hnh trn bt k th mc no m phn gii thnh `/' (to make it so `rm' declines to operate on any directory that resolves to `/'). Ci mc nh vn cho php `rm -rf /' vn hnh khng b ngn tr (to operate unimpeded). Mt ty chn mi khc, `--no-preserve-root' (khng bo tn gc), xa hiu qu ca bt k ty chn `--preserve-root' i trc no. Hy ch rng s hnh x `--preserve-root' c th tr thnh mc nh cho `rm'. (nd: D kh khn trong vic nh ng php ting Anh ng khi son tho, vic vit ng ng php gip hu ht mi ngi nhiu trnh ting Anh c th d dng c v hiu ng (ng vi x-l-gn (slogan) (khu hiu) "Informatics for everyone" (Tin hc cho mi ngi)), li va gip cc trnh dch Anh - Vit (hay Anh - Lo, ...) m c tr thng minh t ra l khng hn con ngi c th d dng dch ng) Cc lnh `chgrp', `chmod' v `chown' cng c th vn hnh kiu hy dit trn ton b cc h thng th bc, vy chng cng h tr cc ty chn ny (so they too support these options). D, khng nh `rm', chng khng thc s ct lin kt (unlink) cc tp tin, cc lnh ny c th cho rng (arguably) l nguy him hn khi vn hnh qui trn `/', do chng thng lm vic nhanh hn nhiu, v do gy thit hi nhiu tp tin hn trc khi mt ngi dng cnh gic c th gin on chng. ---------- Cc ch thch chn trang ---------(1) Nu bn bit mt ci, xin vui lng vit cho . File: coreutils.info, Node: Standards conformance, Prev: Treating / specially, Up: Common options 2.8 S hp cc chun ========================= Trong mt vi trng hp, s hnh x mc nh ca cc tin ch GNU l khng tng thch vi chun POSIX. c ch nhng tnh bt tng thch ny, hy nh ngha bin mi trng `POSIXLY_CORRECT'. Tr khi bn ang kim tra s tun thun POSIX, bn c th khng cn nh ngha `POSIXLY_CORRECT'. Cc phin bn mi hn ca POSIX thnh thong khng tng thch vi cc phin bn c hn. V d, cc phin bn c hn ca POSIX i hi lnh `sort +1' sp xp da trn cc trng th nh v tip theo trong mi dng nhp liu/ d liu nhp (input line), nhng bt u vi POSIX 1003.1-2001, cng lnh c i hi sp xp tp tin m c t tn `+1', v bn phi thay vo dng lnh `sort -k 2' c c s sp xp c da trn trng.Trang 21/369


Cc tin ch GNU thng tun theo phin bn POSIX m chun cho h thng ca bn. lm chng tun theo mt phin bn khc ca POSIX, hy nh ngha bin mi trng `_POSIX2_VERSION' (phin bn posix2) mt gi tr thuc dng YYYYMM m ch r nm v thng m chun c chp thun (adopted). Hai gi tr hin c h tr cho `_POSIX2_VERSION': `199209' i din cho POSIX 1003.2-1992, v `200112' i din cho POSIX 1003.1-2001. V d, nu bn ang chy phn mm c hn m gi nh l mt phin bn c hn ca POSIX v dng `sort +1', `head -1' hay `tail +1', bn c th khc phc (work around) cc vn tnh tng thch bng cch t nh `_POSIX2_VERSION=199209' trong mi trng ca bn. (nd: Cch bit phin bn POSIX ca h iu hnh hin ti?) File: coreutils.info, Node: Output of entire files, Next: Formatting file contents, Prev: Common options, Up: Top 3 u ra ca ton b cc tp tin ************************ Cc lnh ny c v vit ton b cc tp tin, c th chuyn dng (transforming) chng theo cch no . * Menu: * cat invocation:: * tac invocation:: * nl invocation:: * od invocation:: (triu gi cat) Ni ghp v vit cc tp tin. (triu gi tac) Ni ghp v vit cc tp tin ngc chiu. (triu gi nl) nh s cc dng v vit cc tp tin. (triu gi od) Vit cc tp tin theo cc nh dng bt phn hay khc.

File: coreutils.info, Node: cat invocation, Next: tac invocation, Up: Output of entire files 3.1 `cat': Ni ghp v vit cc tp tin ====================================== `cat' chp mi TP_TIN (`-' c ngha l u vo chun), hay u vo chun nu khng c ci no c cho, sang u ra chun. Tm tt: cat [TY_CHN] [TP_TIN]...Trang 22/369


Chng trnh chp nhn cc ty chn sau. Cng hy xem *Note Common options:: (Cc ty chn chung). `-A' `--show-all' Tng ng vi `-vET'. `-B' `--binary' Ch trn MS-DOS v MS-Windows, c v vit cc tp tin theo ch nh phn. Theo mc nh, `cat' trn MS-DOS/MS-Windows dng ch nh phn ch khi u ra chun c ti nh hng n mt tp tin hay mt ng dn; ty chn ny ginh quyn iu . u vo/ u ra tp tin nh phn (Binary file I/O) c dng cc tp tin gi li nh dng ca chng (Vn bn Unix nh i lp vi vn bn v nh phn DOS), vn bn nh i lp vi vn bn v nh phn DOS?), do `cat' thng xuyn c dng nh mt chng trnh chp tp tin. Vi ty chn (hy xem bn di) lm cho `cat' c v vit cc tp tin ch vn bn do trong cc trng hp , ni dung tp tin nguyn thy khng quan trng (v.d., khi cc dng c nh s bi `cat', hay khi cc phn cui dng nn c nh du). iu ny ging nh cc ty chn ny lm vic nh nhng ngi dng DOS/ Windows mong i (This is so Cc ty chn ny work as DOS/Windows users would expect); v d, cc tp tin vn bn phong cch DOS c cc dng ca chng kt thc bng cp k t CR-LF, m s khng c x l nh mt dng trng bi `-b' tr khi tp tin c c ch vn bn. `-b' `--number-nonblank' nh s tt c cc dng u ra/ d liu xut khng trng, khi u bng 1. Trn MS-DOS v MSWindows, ty chn ny lm cho `cat' c v vit cc tp tin ch vn bn. `-e' Tng ng vi `-vE'. `-E' `--show-ends' Hin th mt `$' sau kt thc ca mi dng. Trn MS-DOS v MS-Windows, ty chn ny lm cho `cat' c v vit cc tp tin ch vn bn. `-n'Trang 23/369


`--number' nh s tt c cc dng d liu xut, khi u bng 1. Trn MS-DOS v MS-Windows, ty chn ny lm cho `cat' c v vit cc tp tin ch vn bn. `-s' `--squeeze-blank' Thay th nhiu dng trng lin nhau bng mt dng trng n l. Trn MS-DOS v MS-Windows, ty chn ny lm cho `cat' c v vit cc tp tin ch vn bn. `-t' Tng ng vi `-vT'. `-T' `--show-tabs' Hin t cc k t TAB nh `Î'. `-u' B l i; cho tnh tng thch Unix. `-v' `--show-nonprinting' Hin th cc k t iu khin ngoi tr LFD v TAB bng cch dng ch thch (notation) `^' v t `M-' trc cc k t m c b bit cao (high bit set) (?). Trn MS-DOS v MS-Windows, ty chn ny lm cho `cat' c cc tp tin v u vo chun ch nh phn DOS, vy cc k t CR tn cng ca mi dng cng hu hnh.

Mt tnh trng thot s khng ch ra s thnh cng, v mt gi tr khc khng ch ra s tht bi. File: coreutils.info, Node: tac invocation, Next: nl invocation, Prev: cat invocation, Up: Output of entire files 3.2 `tac': Ni ghp v vit cc tp tin ngc chiu ================================================= (nd: ci t "tac" l mt kiu chi ch nghch ngm, ging nh "more" v "less" vy, c l ca cng ng ngun m, l dng vit ngc ca "cat". iu ny chng c trong HH "nghim tc" DOS/Trang 24/369


Windows. Vui y ch! ;^)) `tac' chp mi TP_TIN (`-' c ngha l u vo chun), hay u vo chun nu khng c g c cho, n u ra chun, o ngc cc bn ghi (records) (cc dng theo mc nh) trong mi ci mt cch tch bit (in each separately). Tm tt: tac [TY_CHN]... [TP_TIN]... "Cc bn ghi" (Records) c phn cch bi cc th hin (instances) ca mt chui (newline theo mc nh). Theo mc nh, chui phn cch (separator string) ny c gn vo tn cng ca bn ghi m n theo sau trong tp tin. Chng trnh chp nhn cc ty chn sau. Cng hy xem *Note Common options:: (Cc ty chn chung). `-b' `--before' (trc) Du phn cch (separator) c gn vo khi u ca bn ghi m n ng trc trong tp tin. `-r' `--regex' (regular expression - biu thc chnh qui) X l chui phn cch nh mt biu thc chnh qui. Cc ngi dng `tac' trn MS-DOS/MSWindows nn ch rng, do `tac' c cc tp tin ch nh phn, mi dng ca mt tp tin vn bn c th kt thc bng mt cp CR/LF thay v LF phong cch Unix. `-s DU_PHN_CCH' `--separator=DU_PHN_CCH' Dng DU_PHN_CCH nh du phn cch bn ghi, thay v newline.

Mt tnh trng thot s khng ch ra s thnh cng, v mt gi tr khc khng ch ra s tht bi. File: coreutils.info, Node: nl invocation, Next: od invocation, Prev: tac invocation, Up: Output of entire files 3.3 `nl': nh s cc dng v vit cc tp tin ======================================Trang 25/369


`nl' vit mi TP_TIN (`-' c ngha l u vo chun), hay u vo chun nu khng c g c cho, vo u ra chun, vi cc s ca dng m c thm vo vi hay tt c cc dng. Tm tt: nl [TY_CHN]... [TP_TIN]... `nl' phn li (decomposes) d liu nhp ca n thnh cc trang (lun l) ((logical) pages); theo mc nh, s ca dng c ti t nh v 1 nh ca mi trang lun l. `nl' x l tt c cc tp tin u vo nh mt ti liu n l; n khng ti t nh cc s ca dng hay cc trang lun l gia cc tp tin. Mt trang lun l gm ba phn: tiu (header), thn (body), v vn bn chn trang (footer - cn phn bit vi "ch thch chn trang" (footnote)). Bt k ci no trong cc phn c th trng. Mi ci c th c nh s theo mt phong cch khc vi nhng ci cn li. Cc khi u ca cc phn ca cc trang lun l c ch ra trong tp tin u vo bi mt dng m cha chnh xc mt trong s cc chui du phn ranh/ du tch/ du gii hn (delimiter strings) ny: `\:\:\:' khi u ca tiu ; `\:\:' khi u ca thn; `\:' khi u ca footer. Hai k t m t cc chui ny c lm ra c th c thay i t `\' v `:' qua cc ty chn (hy xem bn di), nhng kiu thc (pattern) v chiu di ca mi chui khng th b thay i. Mt du gii hn phn (section delimiter) c thay th bng mt dng trng trn u ra. Bt k vn bn no m n trc chui du gii hn phn u tin trong tp tin u vo c xem nh l thnh phn ca mt phn thn, vy `nl' x l tp tin m khng cha cc du gii hn phn no nh mt phn thn n l. Chng trnh chp nhn cc ty chn sau. Cng hy xem *Note Common options:: (Cc ty chn chung).

Trang 26/369


`-b PHONG_CCH' `--body-numbering=PHONG_CCH' Chn phong cch (style) nh s cho cc dng trong phn thn ca mi trang lun l. Khi mt dng khng c nh s, s ca dng hin ti khng c tng ln, nhng k t du phn cch s ca dng vn c chp ni vo trc (prepended) dng. Cc phong cch l: à' nh s tt c cc dng, `t' ch nh s cc dng khng trng (mc nh cho thn), `n' khng nh s cc dng (mc nh cho tiu v footer), `pBRE' ch nh s cc dng m cha mt s so khp (match) cho biu thc chnh qui c bn (basic regular expression) BRE. *Note Regular Expressions: (grep)Regular Expressions. `-d CD' `--section-delimiter=CD' t nh cc k t du gii hn phn CD; mc nh l `\:'. Nu ch c C c cho, ci th hai vn l `:'. (Hy nh bo v `\' hay cc siu k t (metacharacters) khc khi s khai trin h v (shell expansion) vi cc du nhy n (quotes) hay cc du vch xin ngc (backslashes) thm.) `-f PHONG_CCH' `--footer-numbering=PHONG_CCH' Tng t vi `--body-numbering'. `-h PHONG_CCH' `--header-numbering=PHONG_CCH' Tng t vi `--body-numbering'. `-i S' `--page-increment=S' Gia tng cc s ca dng bng mt lng l S (mc nh 1).

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`-l S' `--join-blank-lines=S' Xem nh S (mc nh 1) dng trng lin tip l mt dng lun l cho vic nh s, v ch nh s ci cui cng. ni m s dng trng lin tip t hn S xy ra (Where fewer than NUMBER consecutive empty lines occur), khng nh s chng. Mt dng trng l ci m khng cha cc k t no, thm ch khng c cc du cch hay cc du tab. `-n NH_DNG' `--number-format=NH_DNG' Chn nh dng nh s dng (mc nh l `rn'): `ln' c sp ch thng hng tri (left justified), khng c cc s khng dn u no; `rn' c sp ch thng hng phi, khng c cc s khng dn u no; `rz' c sp ch thng hng phi, cc s khng dn u. `-p' `--no-renumber' Khng ti t nh s ca dng khi u ca mt trang lun l. `-s CHUI' `--number-separator=CHUI' Phn cch s ca dng khi dng vn bn trong u ra bng CHUI (mc nh l k t TAB). `-v S' `--starting-line-number=S' t nh s ca dng khi u trn mi trang lun l S (mc nh 1). `-w S' `--number-width=S' Dng S k t cho cc s ca dng (mc nh 6).

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Mt tnh trng thot s khng ch ra s thnh cng, v mt gi tr khc khng ch ra s tht bi. File: coreutils.info, Node: od invocation, Prev: nl invocation, Up: Output of entire files 3.4 òd': Vit cc tp tin theo cc nh dng bt phn hay khc =============================================== òd' vit mt s biu din r rng (unambiguous representation) ca mi TP_TIN (`-' c ngha l u vo chun), hay u vo chun nu khng c g c cho. Cc tm tt: od [TY_CHN]... [TP_TIN]... od --traditional [TP_TIN] [[+]OFFSET [[+]NHN]] Mi dng d liu xut gm offset ( lch) u vo, m c theo sau bi cc nhm d liu t tp tin. Theo mc nh, òd' in offset bng s bt phn, v mi nhm d liu tp tin l hai byte d liu nhp m c in nh mt s bt phn n l. Chng trnh chp nhn cc ty chn sau. Cng hy xem *Note Common options:: (Cc ty chn chung). `-A C_S' `--address-radix=C_S' Chn c s (base) m theo cc offset tp tin c in. C_S (RADIX) c th l mt trong nhng ci sau: `d' thp phn; ò' bt phn; `x' thp lc phn; `n' khng c g (khng in cc offset).

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Ci mc nh l bt phn. `-j S_BYTE' `--skip-bytes=S_BYTE' B qung (Skip) S_BYTE byte d liu nhp trc khi nh dng v vit. Nu S_BYTE bt u bng `0x' hay `0X', n c din dch theo thp lc phn; nu khng, nu n bt u bng `0', theo bt phn; nu khng, theo thp phn. Vic chp ni `b' nhn S_BYTE vi 512, `k' vi 1024, v `m' vi 1048576. `-N S_BYTE' `--read-bytes=S_BYTE' Xut liu nhiu nht l S_BYTE byte d liu nhp. Cc tin t v cc hu t trn `bytes' c din dch nh cho ty chn `-j'. `-s N' `--strings[=N]' Thay v u ra bnh thng, ch xut liu "cc hng chui" (string constants): t nht l N k t ha ASCII lin tip, m c theo sau bi mt byte rng (null) (s khng). Nu N b b i bng `--strings', ci mc nh l 3. Trn cc h thng c hn, òd' GNU thay vo h tr mt ty chn li thi `-s[N]', trong N cng mc nh 3. Cc Chun POSIX 1003.1-2001 (*note Standards conformance:: (S tun theo cc chun)) khng cho php `-s' m khng c mt tham s; hy dng `--strings' thay vo. `-t LOI' `--format=LOI' Chn nh dng m theo xut liu cc d liu tp tin (Select the format in which to output the file data). LOI (TYPE) l mt chui mt k t ch th loi (type indicator characters) hay nhiu hn di y. Nu bn gm vo nhiu hn mt k t ch th loi trong mt chui LOI n l, hay dng ty chn ny nhiu hn mt ln, òd' vit mt bn sao ca mi dng d liu xut bng cch dng mi trong s cc loi d liu m bn ch r, theo th t m bn ch r. Vic thm mt "z" i cui vo bt k s ch r loi no s chp ni mt s hin th ca s biu din/ s i din (representation) k t ASCII ca cc k t c th in vo dng d liu xut m c sinh bi s ch r loi. (nd: "representation" c l c dch l "s i din" l hp l nht y.)Trang 30/369


à' k t c t tn `c' k t ASCII hay backslash escape (ASCII character or backslash escape), `d' thp phn c nh du hiu (signed decimal) `f' im ph ng/ im l/ du chm ng (floating point) ò' bt phn ù' thp phn khng c nh du hiu (unsigned decimal) `x' thp lc phn Loi à' xut liu nhng th nh `sp' cho du cch, `nl' cho newline, v `nul' cho mt byte rng (null) (s khng). Loi `c' xut liu ` ', `\n', v `\0', mt cch tng ng. Ngoi tr cc loi à' v `c', bn c th ch r s cc byte dng trong vic din dch mi s trong loi d liu (data type - nu ni v lp trnh, n c dch ng hn l "kiu d liu") c cho bng cch theo sau k t ch th loi bng mt s nguyn thp phn. Mt cch thay th, bn c th ch r kch c ca mt trong cc loi d liu ni trang ca trnh bin dch C bng cch theo sau k t ch th loi bng mt trong cc k t sau. Cho cc s nguyn (`d', ò', ù', `x'): `C' char (character - k t) `S' short (s nguyn ngn?)

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Ì' int (s nguyn) `L' long (s nguyn di?) Cho du chm ng (floating point - s thc?) (`f'): F float (s thc?) D double (s thc gp i?) L long double (s thc gp i di?) (nd: mun hiu cc loi/ kiu d liu lp trnh C ny, ngi dng/ c gi tt nhin phi hiu bit v lp trnh C. Chng non nt g!) `-v' `--output-duplicates' Xut liu cc dng lin tip m ging ht nhau. Theo mc nh, khi hai dng d liu xut lin tip hay nhiu hn ging ht nhau, òd' xut liu ch dng u tin, v t ch mt du hoa th trn dng tip theo biu th s c lc (elision). `-w N' `--width[=N]' B i (Dump) `n' byte d liu nhp cho mi dng d liu xut. Ci ny phi l mt bi s ca bi s t thng thng nht/ bi s chung nh nht (least common multiple - tr thng minh ca trnh dch c th gp th thch y) ca cc kch c m c lin kt vi cc kiu (types) d liu xut c ch r. Nu ty chn ny khng c cho g c, ci mc nh l 16. Nu N b b i vi `--width', ci mc nh l 32. Trn cc h thng c hn, òd' GNU thay vo h tr mt ty chn li thi `-w[N]', trong N cng mc nh 32. POSIX 1003.1-2001 (*note Standards conformance:: (S tun theo cc chun)) khng cho php `-w' m khng c mt tham s; hy dng `--width' thay vo.

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Vi ty chn tip theo l cc th tc k (shorthands) cho nhng s nh r nh dng. òd' GNU chp nhn bt k t hp cc th tc k v cc ty chn ch r nh dng no. Cc ty chn ny tch ly. `-a' Xut liu nh cc k t c t tn. Tng ng vi `-ta'. `-b' Xut liu nh cc byte bt phn. Tng ng vi `-toC'. `-c' Xut liu nh cc k t ASCII hay backslash escapes. Tng ng vi `-tc'. `-d' Xut liu nh cc s nguyn ngn thp phn khng c nh du hiu (?) (unsigned decimal shorts). Tng ng vi `-tu2'. `-f' Xut liu nh cc s thc (floats). Tng ng vi `-tfF'. `-h' Xut liu nh cc s nguyn ngn thp lc phn (hexadecimal shorts). Tng ng vi `-tx2'. `-i' Xut liu nh cc s nguyn ngn thp phn (decimal shorts). Tng ng vi `-td2'. `-l' Xut liu nh cc s nguyn di thp phn (decimal longs). Tng ng vi `-td4'. `-o' Xut liu nh cc s nguyn ngn bt phn (octal shorts). Tng ng vi `-to2'. `-x' Xut liu nh cc s nguyn ngn thp lc phn. Tng ng vi `-tx2'. `--traditional' on nhn cc tham s khng phi ty chn (non-option arguments - ngha l cc tham s m ngTrang 33/369


c lp, khng c ty chn m n thuc v pha trc) m òd' truyn thng chp nhn. C php sau: od --traditional [TP_TIN] [[+]OFFSET[.][b] [[+]NHN[.][b]]] c th c dng ch r nhiu nht l mt tp tin v cc tham s ty chn (optional arguments ngha l cc tham s m bt buc phi ng sau ty chn no th mi c gi tr?) m ch r mt offset v mt a ch khi u gi (pseudo-start address), NHN. Theo mc nh, OFFSET c din dch nh mt s bt phn m ch r bao nhiu byte u vo cn b qung trc khi nh dng v vit. Du chm thp phn i cui ty chn p buc s din dch ca OFFSET nh mt s thp phn. Nu khng c s thp phn no c ch r (If no decimal is specified) v offset bt u vi `0x' hay `0X', n c din dch nh mt s thp lc phn. Nu c mt `b' i cui, s cc byte m b b qung s l OFFSET m c nhn vi 512. Tham s NHN c din dch ng/ ch nh OFFSET (interpreted just like OFFSET), nhng n ch r mt a ch gi ban u (initial pseudo-address). Cc a ch gi c hin th trong cc du ngoc n m theo sau bt k a ch bnh thng no.

Mt tnh trng thot s khng ch ra s thnh cng, v mt gi tr khc s khng ch ra s tht bi. File: coreutils.info, Node: Formatting file contents, Next: Output of parts of files, Prev: Output of entire files, Up: Top 4 nh dng ni dung tp tin ************************** Cc lnh ny ti nh dng ni dung cc tp tin. * Menu: * fmt invocation:: * pr invocation:: tin cho vic in. * fold invocation:: r. (triu gi fmt) Ti nh dng vn bn ca on vn (paragraph text). (triu gi pr) nh s trang hay nh s ct (Paginate or columnate) cc tp (triu gi fold) Gi (Wrap) cc dng u vo va vo chiu rng c ch

File: coreutils.info, Node: fmt invocation, Next: pr invocation, Up: Formatting file contents

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4.1 `fmt': Ti nh dng vn bn on vn ================================== `fmt' in y (fills) v ni cc dng sinh cc dng u ra (nhiu nht l) mt s c cho cc k t (75 theo mc nh). Tm tt: fmt [TY_CHN]... [TP_TIN]... `fmt' c t cc tham s TP_TIN c ch r (hay u vo chun nu khng c g c cho), v vit vo u ra chun. Theo mc nh, cc dng trng, cc du cch m gia cc t, v s tht u dng (indentation) c bo ton trong d liu xut; cc dng u vo lin tip m vi s tht u dng khc nhau khng c ni; cc du tabs c trin khai (expanded) trn u vo v c gii thiu (introduced) trn u ra. `fmt' chung cc dng ngt/ s ngt cc dng tn cng ca mt cu (breaking lines at the end of a sentence) hn, v c trnh cc du ngt dng (line breaks) sau t u tin ca mt cu hay trc t cui cng ca mt cu. Mt "du ngt cu" (sentence break) c nh ngha nh tn cng ca mt on vn hoc mt t m kt thc bng bt k ci no trong s `.?!', m c theo sau bi hai du cch hay end of line, l i bt k cc du ngoc n hay cc du nhy n/ du trch dn (quotes) xen gia no. Nh TeX, `fmt' c ton b "cc on vn" trc khi chn cc du ngt dng; thut ton l mt bin th ca ci m trong "Breaking Paragraphs Into Lines" (Ngt cc on vn thnh cc Dng) (Donald E. Knuth v Michael F. Plass, `Software--Practice and Experience' (Phn mm -- Thc tin v Kinh nghim), 11 (1981), 1119-1184). (nd: mt s ti liu hng dn son vn bn khc ni rng ch ci u tin ca cu tip theo nn cch du chm cu ca cu u tin l mt du cch) Chng trnh chp nhn cc ty chn sau. Cng hy xem *Note Common options:: (Cc ty chn chung). `-c' `--crown-margin' Ch "Crown margin" (l trn cng): bo ton s tht u dng ca hai dng u tin m trong vng mt on vn, v canh thng hng (align) l tri ca mi dng tip theo vi ci ca dng th hai.

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`-t' `--tagged-paragraph' Ch "Tagged paragraph" (on vn c gn th): ging ch l trn cng, ngoi tr rng nu s tht u dng ca dng u tin ca mt on vn ging nh s tht u dng ca ci th hai, dng u tin c x l nh mt on vn mt dng. `-s' `--split-only' Ch chia tch cc dng. Khng ni cc dng ngn hnh thnh nhng ci di hn. iu ny ngn nga cc dng m mu (sample lines of code), v vn bn "c nh dng" nh th khc khi vic b kt hp mt cch qu ng (unduly combined). `-u' `--uniform-spacing' S nh du cch ng dng (Uniform spacing). Lm gim s nh du cch gia cc t cn mt du cch, v s nh du cch gia cc cu cn hai du cch. `-WIDTH' `-w CHIU_RNG' `--width=CHIU_RNG' in y cc dng d liu xut ln n CHIU_RNG k t (mc nh 75). `fmt' ban u c lm cho cc dng ngn khong 7% hn ci ny, cho n khng gian cn bng cc chiu di dng. `-p TIN_T' `--prefix=TIN_T' Ch c cc dng m bt u bng TIN_T (c th c i trc bi cc du cch trng (whitespace)) l l thuc vo vic nh dng. Tin t v bt k du cch trng i trc no l b lt i cho vic nh dng v ri c gn li vo mi dng d liu xut c nh dng. Mt s dng l nh dng cc loi no ca cc ch thch chng trnh, trong khi mc m khng b thay i.

Mt tnh trng thot s khng ch ra s thnh cng, v mt gi tr khc s khng ch ra s tht bi. File: coreutils.info, Node: pr invocation, Next: fold invocation, Prev: fmt invocation, Up: Formatting file contents 4.2 `pr': nh s trang hay nh s ct cc tp tin cho vic inTrang 36/369


================================================== `pr' vit mi TP_TIN (`-' c ngha l u vo chun), hay u vo chun nu khng c g c cho, vo u ra chun, bng cch nh s trang v theo ty chn l xut liu theo nh dng nhiu ct; theo ty chn th ha trn tt c cc TP_TIN, in tt c kiu song song, mt ci cho mi ct (printing all in parallel, one per column). Tm tt: pr [TY_CHN]... [TP_TIN]... Theo mc nh, mt header 5 dng c in mi trang: hai dng trng; mt dng vi ngy thng, tn tp tin, v s m trang; v thm hai dng trng. Mt footer nm dng trng cng c in. Vi ty chn `-F', mt header 3 dng c in: hai dng trng dn u c b i; khng c footer no c dng. PAGE_LENGTH (chiu di trang) mc nh trong c hai trng hp l 66 dng. S mc nh ca cc dng vn bn thay i t 56 (khng c `-F') n 63 (c `-F'). Dng vn bn ca header ly dng (takes the form) `DATE STRING PAGE' (NGY_THNG CHUI TRANG), vi cc du cch m c chn quanh STRING dng chim PAGE_WIDTH (chiu rng trang) y . y, DATE (NGY_THNG) l ngy thng (hy xem ty chn `-D' hay `--date-format' cho cc chi tit), STRING (chui) l chui header c t gia, v PAGE bng vi (identifies) s trang. Hng mc qui c a phng (locale category) `LC_MESSAGES' nh hng n vic nh vn (spelling) ca PAGE; theo qui c a phng C mc nh, n l `Page S' trong S l s trang thp phn. Cc d liu np biu mu (Form feeds) trong u vo gy ra cc du ngt trang trong u ra. Nhiu d liu np biu mu sinh ra cc trang trng. Cc ct c (are of) chiu rng bng nhau, m c phn cch bi mt chui ty chn (mc nh l `space' (du cch) (nd: ch ny dch ra sao?)). Cho d liu xut nhiu ct, cc dng s lun b ct ct PAGE_WIDTH (mc nh 72), tr khi bn dng ty chn `-J'. Cho d liu xut ct n, khng c s ct ct dng no xy ra theo mc nh. Hy dng ty chn `-W' ct ct cc dng trong trng hp . Cc thay i sau c lm trong phin bn 1.22i v p dng cho cc phin bn v sau (later) ca `pr': - Brian * Vi TY CHN CH CI nh (`-s', `-w') c ti nh ngha cho s tun thun POSIX tt hn. D liu xut ca vi trng hp thm (some further cases) c lm cho thch nghi vi cc h thng Unix khc. Cc thay i ny khng tng thch vi cc phin bn sm hn ca chng trnh. * Vi ty chn CH CI IN HOA MI (`-J', `-S', `-W') c gii thiu tt i nhng s cn tr khng c mong i ca cc ty chn ch ci nh. Ty chn `-N' v tham s th haiTrang 37/369


TRANG_CUI_CNG ca `+TRANG_U_TIN' cho nhiu tnh linh hot hn. S thao tc c nu chi tit (detailed handling) ca cc d liu np biu mu m c t nh trong cc tp tin u vo i hi ty chn `-T'. * Cc ty chn ch ci in hoa ginh quyn cc ci ch ci nh. * Vi trong s cc tham s ty chn (option-arguments) (hy so snh `-s', `-e', `-i', `-n') khng th c ch r nh cc tham s tch bit t ch ci ty chn i trc ( c pht biu ri trong s nh r (specification) POSIX). Chng trnh chp nhn cc ty chn sau. Cng hy xem *Note Common options:: (Cc ty chn chung). `+TRANG_U_TIN[:TRANG_CUI_CNG]' `--pages=TRANG_U_TIN[:TRANG_CUI_CNG]' Bt u vic in vi trang TRANG_U_TIN v dng vi TRANG_CUI_CNG. Vic mt `:TRANG_CUI_CNG' ng kt thc tp tin. Trong khi c on s cc trang c nhy qung, mi d liu np biu mu trong tp tin u vo to ra mt trang mi. Vic m trang m c v khng c `+TRANG_U_TIN' l ging ht. Theo mc nh, vic m bt u bng trang u tin ca tp tin u vo (khng phi trang u tin c in (not first page printed)). Vic nh s dng c th c thay i (altered) bi ty chn `-N'. `-CT' `--columns=CT' Vi mi TP_TIN n l, sinh ra CT ct d liu xut (mc nh l 1) v tin cc ct xung (print columns down), tr khi `-a' c dng. Chiu rng ct c gim t ng khi/ do (as) CT tng; tr khi bn cng dng ty chn `-W/-w' tng CHIU_RNG_TRANG. Ty chn ny rt c th lm cho (This option might well cause) vi dng b ct ct. S cc dng trong cc ct trn mi trang c cn bng. Cc ty chn `-e' v `-i' l bt (are on) cho u ra nhiu ct vn bn (multiple text-column output). Cng vi ty chn `-J', s canh thng ct v s ct ct dng c tt i. Cc dng c chiu di y c ni theo mt nh dng khng c trng/ trng t do (are joined in a free field format) v ty chn `-S' c th t nh cc du phn cch trng. `-COLUMN' khng c php dng (may not be used) vi ty chn `-m'. (nd: t "free" l mt t nguy him, va c ngha l "khng c" (VD: "free of charge" c ngha l "min ph"), va c ngha l "t do")

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`-a' `--across' Vi mi TP_TIN n l, in cc ct ngang qua (across) hn l xung. Ty chn `-COLUMN' phi c cho vi CT (COLUMN) ln hn mt. Nu mt dng l qu di n mc khng th va vn (If a line is too long to fit) trong mt ct, n b ct ct. (nd: Vic cho tn ca v d (nh COLUMN (CT) trn) trng tn vi ty chn (-COLUMN) trong nguyn bn ting Anh cng gy kh khn khi dch) `-c' `--show-control-chars' In cc k t iu khin bng cch dng s ghi ch (notation) m (v.d., `^G'); in cc k t khng in (nonprinting) khc trong s ghi ch du vch xin ngc bt phn (octal backslash notation). Theo mc nh, cc k t khng in khng b thay i. `-d' `--double-space' nh du cch kp d liu xut (Double space the output). (nd: "Double space" c coi l MT ng t, hi kh dch v c v bt qui tc vi ting Anh thng thng) `-D NH_DNG' `--date-format=NH_DNG' nh dng cc ngy thng header bng cch dng NH_DNG, dng cng cc qui c nh cho lnh `date +NH_DNG'; *Note date invocation::. Ngoi tr cc hng dn (directives), m bt u bng `%', cc k t trong NH_DNG c in khng i (are printed unchanged) (nd: hi bt qui tc?). Bn c th dng ty chn ny ch r mt chui ty ch ca (in place of) ngy thng header/ header ngy thng (header date), v.d., `--date-format="Monday morning"' (nd: "Bui sng th Hai". C tr ngi v Unicode ting Vit khng?). Nu bin mi trng `POSIXLY_CORRECT' khng c t nh, nh dng ngy thng mc nh `%Y-%m-%d %H:%M' (nd: %NM-%thng-%ngy_trong_thng %GI:%PHT) (v d, `2001-12-04 23:59'); nu khng, nh dng ph thuc vo hng mc qui c a phng `LC_TIME', vi ci mc nh m l `%b %e %H:%M %Y' (nd: "b" v "e" == ?) (v d, `Dec 4 23:59 2001' (nd: thng_Chp 4 23:59 2001).

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`-e[IN-TABCHAR[IN-TABWIDTH]]' `--expand-tabs[=IN-TABCHAR[IN-TABWIDTH]]' Trin khai cc du TAB thnh cc du cch trn u vo (Expand TABs to spaces on input). Tham s ty chn IN-TABCHAR (nd: ng ra phi l "IN_TABCHAR" v c dch l "K_T_TAB_U_VO" v n l v d?) l k t tab u vo (mc nh l k t TAB). Tham s ty chn th hai IN-TABWIDTH (nd: cng th, ng l l "IN_TABWIDTH" == "CHIU_RNG_TAB_U_VO"?) l chiu rng ca k t tab u vo (mc nh l 8). `-f' `-F' `--form-feed' Dng mt form feed thay v cc newline phn cch cc trang u ra. Chiu di trang mc nh 66 dng khng b thay i. Nhng s cc dng vn bn mi trang thay i t 56 mc nh n 63 dng. (nd: Thc ra "form feed" l g? Chc khng th dch l "d liu np biu mu") `-h TIU_' `--header=TIU_' Thay th tn tp tin trong header bng chui c canh gia TIU_. Khi dng h v, TIU_ nn c t gia hai du nhy n (quoted) v nn c phn cch khi `-h' bi mt du cch. `-i[OUT-TABCHAR[OUT-TABWIDTH]]' `--output-tabs[=OUT-TABCHAR[OUT-TABWIDTH]]' Thay th cc du cch bng cc TAB trn d liu xut. Tham s ty chn OUT-TABCHAR (nd: K_T_TAB__U_RA) l k t tab d liu xut (mc nh l k t TAB). Tham s ty chn th nh OUT-TABWIDTH (nd: CHIU_RNG_TAB_U_RA) l chiu rng ca k t tab d liu xut (mc nh l 8). `-J' `--join-lines' Ha trn cc dng c chiu di y . c dng cng vi cc ty chn ct `-COLUMN', `-a -COLUMN' hay `-m'. Tt i s ct ct dng `-W/-w'; khng c s canh thng ct no c dng (no column alignment used); c th c dng vi `--sep-string[=CHUI]'. `-J' c gii thiu (cng vi `-W' v `--sep-string') g ri cc ty chn c (tun theo POSIX) `-w' v `-s' km theo ba ty chn ct. `-l CHIU_DI_TRANG'Trang 40/369


`--length=CHIU_DI_TRANG' t nh chiu di trang CHIU_DI_TRANG (mc nh 66) dng, gm cc dng ca header [v footer]. Nu CHIU_DI_TRANG t hn hay bng 10 (hay test: integer expression expected before -eq"="li--> test: biu thc s nguyn c mong i trc -eq" File: coreutils.info, Node: Connectives for test, Prev: Numeric tests, Up: test invocation 16.3.6 Cc th ni (Connectives) cho `test' ----------------------------Cc th ni lun l thng dng (The usual logical connectives). `! B_THC' True nu B_THC (EXPR) l false.

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`B_THC1 -a B_THC2' True nu c hai B_THC1 (EXPR1) v B_THC2 (EXPR2) l true. `B_THC1 -o B_THC2' True nu mi B_THC1 hay B_THC2 l true.

File: coreutils.info, Node: expr invocation, Prev: test invocation, Up: Conditions 16.4 èxpr': Lng gi cc biu thc ================================= èxpr' lng gi mt biu thc v vit kt qu ln u ra chun. Mi biu hin (token) ca biu thc phi l mt tham s cch bit. Cc ton hng (Operands) l cc s nguyn hay cc chui. Cc s nguyn gm mt ch s thp phn hay nhiu hn, vi mt `-' i u theo ty chn. èxpr' chuyn i bt k ci g m xut hin mt v tr ton hng thnh mt s nguyn hay mt chui ty vo php ton (operation) m ang c p dng vo n. Cc chui khng c ng ngoc trch dn cho chnh èxpr', d bn c th cn ng ngoc trch dn chng bo v cc k t vi ngha c bit vi h v, v.d., cc du cch. Tuy nhin, bt chp vic n c c ng ngoc trch dn hay khng, mt ton hng chui khng nn l mt du ngoc n (parenthesis) hay bt k ci no trong s cc ton t ca èxpr' nh `+', vy bn khng th an ton truyn (pass) mt chui ty `$str' n expr ch bng cch ng ngoc trch dn n n h v. Mt cch khc phc (work around) iu ny l dng phn m rng `GNU' `+', (v.d., `+ "$str" = foo'); mt cch c tnh d mang hn (more portable way) l dng `" $str"' v iu chnh phn cn li ca biu thc tnh n du cch i u (take the leading space into account) (v.d., `" $str" = " foo"'). Bn khng nn truyn mt s nguyn m hay mt chui vi `-' i u nh tham s u tin ca èxpr', do n c th b din dch sai nh mt ty chn; iu ny c th c trnh bng s ng ngoc n (parenthesization). Cng th, cc kch bn c tnh d mang khng nn dng mt ton hng chui m tnh c l c dng mt s nguyn (that happens to take the form of an integer); iu ny c th c khc phc bng cch chn cc du cch i u nh c cp trn. Cc ton t c th c cho nh cc k hiu trung t (infix symbols) hay cc t kha tin t (prefix keywords). Cc du ngoc n (Parentheses) c th c dng cho vic gom nhm theo cch thcTrang 196/369


thng dng. Tuy th, bn phi ng ngoc trch dn cc du ngoc n v nhiu ton t (You must quote parentheses and many operators) trnh h v lng gi chng (to avoid the shell evaluating them). Tnh trng thot: 0 nu biu thc khng l null hay khng l 0, 1 nu biu thc l null hay 0, 2 nu biu thc l v hiu lc theo c php (syntactically invalid), 3 nu mt li xy ra. * Menu: * String expressions:: * Numeric expressions:: * Relations for expr:: * Examples of expr:: (Cc biu thc chui) + : match substr index length (Cc biu thc s) + - * / % (Cc quan h cho expr) | & < = > (Cc v d cho expr) Cc v d.

File: coreutils.info, Node: String expressions, Next: Numeric expressions, Up: expr invocation 16.4.1 Cc biu thc chui ------------------------èxpr' h tr vic so khp dng thc (pattern matching) v cc ton t chui khc. Nhng ci ny c quyn i trc (precedence) thp hn c hai ton t s v quan h (numeric and relational operators) (trong cc phn (sections) tip theo). `CHUI : B_THC' Thc hin vic so khp dng thc. Cc tham s c chuyn i thnh cc chui v ci th nh c xem l mt (basic, a la GNU `grep') biu thc chnh qui (a (basic, a la GNU `grep') regular expression), vi mt `^' m c ghp ni vo trc mt cch tng minh (with a `^' implicitly prepended). Tham s u tin sau c so khp vi (matched against) biu thc chnh qui ny. Nu s so khp (the match) thnh cng v B_THC_C_QUI (REGEX) dng `$' v `$', biu thc `:' tr v phn ca CHUI m so khp vi biu thc con (that matched the subexpression); nu khng, n tr v s cc k t m c so khp.

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Nu s so khp tht bi, ton t `:' tr v chui rng (null string) nu `$' v `$' c dng trong B_THC_C_QUI, nu khng th 0. Ch c cp `$ ... $' u tin l thch hp vi gi tr tr v (the return value); cc cp thm l c ngha ch cho vic gom nhm cc ton t biu thc chnh qui. Trong biu thc chnh qui, `\+', `\?', v `\|' l cc ton t m mt cch tng ng so khp vi mt hay nhiu hn, s khng hay mt, hay cc th thay th cch bit (respectively match one or more, zero or one, or separate alternatives). Cc èxpr' ca SunOS v ci khc x l nhng ci ny nh cc k t thng (regular characters). (POSIX cho php mt trong hai s hnh x (allows either behavior).) *Note Regular Expression Library: (regex)Top (Th vin Biu thc Chnh qui: nh), cho cc chi tit v c php biu thc chnh qui. Vi v d l trong *Note Examples of expr:: (Cc v d v expr). `match CHUI B_THC_C_QUI' Mt cch thay th (alternative way) lm vic so khp dng thc. Ci ny ging nh `CHUI : B_THC_C_QUI'. `substr CHUI V_TR CHIU_DI' Tr v chui con (substring) ca CHUI m bt u V_TR vi chiu di m nhiu nht l CHIU_DI. Nu V_TR hay CHIU_DI u m, khng, hay khng phi kiu s, tr v chui rng. ìndex CHUI B_K_T' Tr v v tr u tin trong CHUI ni m k t u tin trong B_K_T (CHARSET) c tm ra. Nu khng c k t no trong B_K_T c tm ra trong CHUI, tr v 0. `length CHUI' Tr v chiu di ca CHUI. `+ TOKEN' Din dch TOKEN nh mt chui, ngay c nu n l mt t kha nh MATCH hay mt ton t nh `/'. iu ny lm vic kim tra èxpr length + "$x"' hay èxpr + "$x" : '.*/$.$'' l c th v khin n lm iu ng n ngay c nu gi tr ca $X ngu nhin l (v d) `/' hay ìndex'. Ton t ny l mt phn m rng GNU (GNU extension). Cc kch bn h v c tnh d mang nn dng `" $token" : ' $.*$'' thay v `+ "$token"'. (Nd: "TOKEN" l tn mt din vin ngi Nht? Nu khng, n l ci qui g?)Trang 198/369


(Nd: Trong mt s b mu ch, nh Times New Roman chng hn, hai du nhy n (') ng k nhau ('') trng chng khc my mt du ngoc kp (")) lm cho èxpr' din dch cc t kha nh cc chui, bn phi dng ton t `quote'. File: coreutils.info, Node: Numeric expressions, Next: Relations for expr, Prev: String expressions, Up: expr invocation 16.4.2 Cc biu thc s -------------------------èxpr' h tr cc ton t s thng dng, theo th t ca quyn i trc (precedence) tng dn. Cc ton t chui (phn (section) trc) c quyn i trc thp hn, cc th ni (connectives) (phn (section) tip theo) c (quyn i trc) cao hn (have higher). `+ -' Php cng (Addition) v php tr (subtraction). C hai tham s c chuyn i thnh cc s nguyn; mt li xy ra nu iu ny khng th c lm. `* / %' Php nhn, php chia, php chia ly d (Multiplication, division, remainder). C hai tham s c chuyn i thnh cc s nguyn; mt li xy ra nu iu ny khng th c lm.

File: coreutils.info, Node: Relations for expr, Next: Examples of expr, Prev: Numeric expressions, Up: expr invocation 16.4.3 Cc quan h cho èxpr' --------------------------èxpr' h tr cc th ni (connectives) v cc quan h lun l thng dng. Nhng ci ny c quyn i trc cao hn cc ton t chui hay s (These _are higher precedence_ than either the string or numeric operators) (cc phn (sections) trc). y l danh sch, ton t c quyn i trc thp nht trc tin. `|' Tr v tham s u tin ca n nu khng l rng hay khng l s khng, nu khng tham s thTrang 199/369


nh ca n nu n khng l rng hay khng l s khng, nu khng l 0. N khng lng gi tham s th nh ca n nu tham s u tin ca n khng l rng hay khng l s khng. `&' Tr v tham s u tin ca n nu khng c tham s no l rng hay s khng (if neither argument is null or zero), nu khng l 0. N khng lng gi tham s th nh ca n nu tham s u tin ca n l rng hay s khng. `< = >' So snh cc tham s v tr v 1 nu quan h l true, nu khng l 0 (0 otherwise). `==' l mt th ng ngha (synonym) cho `='. èxpr' trc tin c chuyn i c hai tham s thnh cc s nguyn v lm mt s so snh s; nu mt trong hai s chuyn i tht bi (if either conversion fails), n lm mt s so snh kiu t in (lexicographic comparison) bng cch dng trnh t i chiu k t m c ch r bi locale `LC_COLLATE'.

File: coreutils.info, Node: Examples of expr, Prev: Relations for expr, Up: expr invocation 16.4.4 Cc v d ca vic dng èxpr' ------------------------------ y l vi v d, m gm vic ng ngoc trch dn cho cc siu k t (metacharacters) h v. cng/ thm (add) 1 vo bin h v `foo', trong cc h v tng thch Bourne: foo=èxpr $foo + 1` (Nd: c ai thy du (`) v du (') khc nhau ra sao khng?) in phn khng phi th mc ca tn tp tin m c tr trong `$fname', m khng cn/ cn khng c cha mt `/' (which need not contain a `/'). expr $fname : '.*/$.*$' '|' $fname (Nd: "fname"="file_name"="tn_tp_tin"="tnttin") Mt v d m cho thy rng `\+' l mt ton t: expr aaa : 'a\+' => 3Trang 200/369


expr abc : 'a$.$c' => b expr index abcdef cz => 3 expr index index a error--> expr: syntax error expr index quote index a => 0 (Nd: "syntax error"="li c php") File: coreutils.info, Node: Redirection, Next: File name manipulation, Prev: Conditions, Up: Top 17 S ti nh hng ************** Cc h v Unix thng thng cung cp vi dng ca "s ti nh hng"--cc cch thay i ngun u vo hay ni n u ra ca mt lnh. Nhng mt s ti nh hng c ch c thc hin bi mt lnh tch bit, khng phi bi h v; n c m t y. * Menu: * tee invocation:: (triu gi tee) Ti nh hng u ra n nhiu tp tin.

File: coreutils.info, Node: tee invocation, Up: Redirection 17.1 `tee': Ti nh hng u ra n nhiu tp tin ============================================= Lnh `tee' chp u vo chun vo u ra chun v cng n bt k cc tp tin no m c cho nh cc tham s. Ci ny c ch khi bn khng ch mun gi (send) vi d liu xung mt ng dn, m cn lu mt bn sao. Tm tt: tee [TY_CHN]... [TP_TIN]... (Nd: "tee" c ging nh cch c ting Anh ca ch ci "T", m c l ngha l "Ng ba lng", tn mtTrang 201/369


b phim Vit Nam ni ting?) Nu mt tp tin m ang c vit vo khng tn ti ri, n c to ra. Nu mt tp tin m ang c vit vo tn ti ri, cc d liu m n cha trc b vit tr khi ty chn `-a' c dng. Chng trnh chp nhn cc ty chn sau. Cng hy xem *Note Common options:: (Cc ty chn chung). `-a' `--append' Chp ghp u vo chun vo cc tp tin c cho hn l vit chng. `-i' `--ignore-interrupts' L i cc tn hiu ngt (interrupt signals).

Mt tnh trng thot s khng ch ra s thnh cng, v mt gi tr khc s khng ch ra s tht bi. File: coreutils.info, Node: File name manipulation, Next: Working context, Prev: Redirection, Up: Top 18 S thao tc tn tp tin ************************* Phn (section) ny m t cc lnh m thao tc cc tn tp tin. * Menu: * basename invocation:: * dirname invocation:: * pathchk invocation:: (triu gi basename) Lt b th mc v hu t khi mt tn tp tin. (triu gi dirname) Lt b hu t khng phi th mc khi mt tn tp tin. (triu gi pathchk) Kim tra tnh d mang ca tn tp tin.

File: coreutils.info, Node: basename invocation, Next: dirname invocation, Up: File name manipulation 18.1 `basename': Lt b th mc v hu t khi mt tn tp tinTrang 202/369


============================================================ `basename' ly i bt k cc thnh phn th mc i u no khi TN. Tm tt: basename TN [HU_T] Nu HU_T c ch r v ging ht vi phn cui ca TN, n cng c ly i khi TN. `basename' in kt qu ln u ra chun. Cc ty chn duy nht l `--help' v `--version'. *Note Common options:: (Cc ty chn chung). Mt tnh trng thot s khng ch ra s thnh cng, v mt gi tr khc s khng ch ra s tht bi. File: coreutils.info, Node: dirname invocation, Next: pathchk invocation, Prev: basename invocation, Up: File name manipulation 18.2 `dirname': Lt b hu t khng phi th mc khi mt tn tp tin =========================================================== `dirname' in tt c tr thnh phn c hn nh bi du s (slash-delimited component) cui cng ca mt chui (c l l mt tn tp tin (presumably a filename)). Tm tt: dirname TN Nu TN l mt thnh phn n l, `dirname' in `.' (m c ngha l th mc hin hnh). Cc ty chn duy nht l `--help' v `--version'. *Note Common options:: (Cc ty chn chung). Mt tnh trng thot s khng ch ra s thnh cng, v mt gi tr khc s khng ch ra s tht bi. File: coreutils.info, Node: pathchk invocation, Prev: dirname invocation, Up: File name manipulation 18.3 `pathchk': Kim tra tnh d mang ca tn tp tin =========================================== `pathchk' kim tra tnh d mang ca cc tn tp tin. Tm tt:

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pathchk [TY_CHN]... TN... Cho mi TN, `pathchk' in mt thng bo l c bt k ci no trong s cc iu kin ny l true khng: 1. mt trong cc th mc hin hu trong TN khng c quyn tm kim (thi hnh) (search (execute) permission), (Nd: Mt th mc (hay mt tp tin) khng c quyn thi hnh th cng khng th c tm ra? Hay l khng th "khm ph" ("explore") bn trong n?) 2. chiu di ca TN ln hn chiu di tn tp tin ti a ca h tp tin ca n, 3. chiu di ca mt thnh phn ca TN, m tng ng vi mt tn th mc hin hu, l ln hn chiu di ti a ca h tp tin ca n cho mt thnh phn tn tp tin. Chng trnh chp nhn ty chn sau. Cng hy xem *Note Common options:: (Cc ty chn chung). `-p' `--portability' Thay v thc hin cc kim tra (checks) chiu di trn h tp tin nn (underlying filesystem), kim tra (test) chiu di ca mi tn tp tin v cc thnh phn ca n so vi (against) cc gii hn ti thiu POSIX cho tnh d mang. Cng kim tra xem (Also check that) tn tp tin khng cha cc k t no m khng trong b k t tn tp tin c tnh d mang.

Tnh trng thot: 0 nu tt c cc tn tp tin c ch r vt qua c tt c cc kim tra ny, 1 nu khng nh th (1 otherwise). File: coreutils.info, Node: Working context, Next: User information, Prev: File name manipulation, Up: Top 19 Ng cnh lm vic/ Bi cnh lm vic/ Hon cnh lm vic (Working context) ****************** Phn (section) ny m t cc lnh m hin th hay thay i ng cnh m trong bn ang lm vic:Trang 204/369


th mc hin hnh, cc t nh (thit b) u cui (the terminal settings), v c th (and so forth). Cng hy xem cc lnh lin quan n ngi dng (user-related commands) trong phn (section) tip theo. * Menu: * pwd invocation:: * stty invocation:: * printenv invocation:: * tty invocation:: (triu gi pwd) In th mc lm vic (Print working directory). (triu gi stty) In hay thay i cc c tnh ca (thit b) u cui. (triu gi printenv) In cc bin mi trng (Print environment variables). (triu gi tty) In tn tp tin ca thit b u cui ln u vo chun.

File: coreutils.info, Node: pwd invocation, Next: stty invocation, Up: Working context 19.1 `pwd': In th mc lm vic =================================== `pwd' in tn c phn gii (resolved) y ca th mc hin hnh. l, tt c cc thnh phn ca tn c in s l cc tn th mc thc s--khng c ci no s l cc lin kt tng trng. Do hu ht cc h v c mt lnh ni trang theo cng tn, vic dng tn lnh trn tri trong mt kch bn hay mt cch tng tc c th cho bn tnh chc nng khc hn ci m c m t y. Cc ty chn duy nht l mt `--help' hay `--version' n c. *Note Common options:: (Cc ty chn chung). Mt tnh trng thot s khng ch ra s thnh cng, v mt gi tr khc s khng ch ra s tht bi. File: coreutils.info, Node: stty invocation, Next: printenv invocation, Prev: pwd invocation, Up: Working context 19.2 `stty': In hay thay i cc c tnh ca thit b u cui ===================================================== `stty' in hay thay i cc c tnh ca thit b u cui, nh l tc baud (baud rate). Cc tm tt: stty [TY_CHN] [T_NH]... stty [TY_CHN]Trang 205/369


Nu cho rng khng c cc t nh ng dy no (If given no line settings), `stty' in tc baud rate, s k cng ng dy (line discipline number) (trn cc h thng m h tr n), v cc t nh ng dy (line settings) m c thay i t cc gi tr m c t nh bi `stty sane'. Theo mc nh, vic c v vic t nh ch (mode reading and setting) c thc hin trn ng dy tty (tty line) m c ni vo u vo chun, d iu ny c th c thay i bi ty chn `--file'. `stty' chp nhn nhiu tham s khng phi ty chn m thay i cc kha cnh (aspects) ca s vn hnh ng dy thit b u cui, nh c m t di y. Chng trnh chp nhn cc ty chn sau. Cng hy xem *Note Common options:: (Cc ty chn chung). `-a' `--all' In tt c cc t nh hin ti theo dng ngi c c. Ty chn ny khng c php dng (may not be used) kt hp vi bt k cc t nh ng dy no. `-F THIT_B' `--file=THIT_B' t nh ng dy m c m bi tn tp tin m c ch r trong THIT_B (DEVICE) thay v ng dy tty m c ni vo u vo chun. Ty chn ny cn thit do vic m mt tty POSIX i hi s dng c Ò_NONDELAY' nga mt tty POSIX khi vic chn (blocking) cho n khi ng dy pht hin th mang/ b ti/ tn hiu mang (carrier detect line) l cao nu c `clocal' khng c t nh. Do , vic cho php h v m thit b theo cch thc truyn thng l khng lun c th. `-g' `--save' In tt c cc t nh hin ti theo mt dng m c th c dng nh mt tham s vi mt lnh `stty' khc phc hi cc t nh hin ti. Ty chn ny khng c php dng kt hp vi bt k cc t nh ng dy no.

Nhiu t nh c th c tt i bng cch t trc (preceding) chng bng mt `-'. Cc tham s nh th c nh du bn di bng "C th c/ b ph nh" (are marked below with "May be negated") trong phn m t ca chng. Chnh cc m t ch n trng hp r rng/ dng tnh/ tch cc (The descriptions themselves refer to the positive case), l, khi _khng_ b ph nh (D nhin,Trang 206/369


tr khi c pht biu khc (stated otherwise)). Vi t nh khng c sn trn tt c cc h thng POSIX, do chng dng cc phn m rng (extensions). Cc tham s nh th c nh du bn di bng "Khng phi POSIX (Non-POSIX)" trong s m t ca chng. Trn cc h thng khng phi POSIX, nhng ci hay cc t nh khc cng c th khng c sn, nhng vic ghi t liu tt c cc bin thin l khng kh thi (but it's not feasible to document all the variations): ch hy th n v xem (just try it and see). Mt tnh trng thot s khng ch ra s thnh cng, v mt gi tr khc s khng ch ra s tht bi. * Menu: * Control:: * Input:: * Output:: * Local:: * Combination:: * Characters:: * Special:: (iu khin) Cc t nh iu khin (u vo) Cc t nh u vo (u ra) Cc t nh u ra (Cc b) Cc t nh cc b (T hp) Cc t nh t hp (Cc k t) Cc k t c bit (c bit) Cc t nh c bit

File: coreutils.info, Node: Control, Next: Input, Up: stty invocation 19.2.1 Cc t nh iu khin ----------------------Cc t nh iu khin: `parenb' Sinh bit chn l (parity bit) u ra v mong i bit chn l u vo. C th b ph nh (_May_ be negated). `parodd' t nh tnh chn l l (odd parity) (ngay c nu b ph nh). C th b ph nh. `cs5' `cs6' `cs7'Trang 207/369


`cs8' t nh kch c k t 5, 6, 7, hay 8 bit. `hup' `hupcl' Gi () mt tn hiu hangup (treo?) khi tin trnh cui cng ng tty. C th b ph nh. `cstopb' Dng hai bit dng (stop bits) mi k t (mt nu b ph nh). C th b ph nh. `cread' Cho php u vo c nhn. C th b ph nh. `clocal' Bt hot cc tn hiu iu khin ca b gii iu bin (modem control signals). C th b ph nh. `crtscts' Hot ha iu khin dng RTS/CTS (RTS/CTS flow control). Khng phi POSIX. C th b ph nh. File: coreutils.info, Node: Input, Next: Output, Prev: Control, Up: stty invocation 19.2.2 Cc t nh u vo --------------------ìgnbrk' L i cc k t ngt (break characters). C th b ph nh. `brkint' Lm cho cc du ngt gy ra mt tn hiu ngt (Make breaks cause an interrupt signal). C th b ph nh. ìgnpar' L i cc k t m vi cc li chn l (parity errors). C th b ph nh. `parmrk' nh du cc li chn l (bng mt trnh t 255-0 k t (255-0-character sequence)). C th b phTrang 208/369


nh. ìnpck' Cho php vic kim tra tnh chn l u vo. C th b ph nh. ìstrip' Xa bit cao (th 8) ca cc k t u vo. C th b ph nh. ìnlcr' Dch newline thnh carriage return (v u dng). C th b ph nh. ìgncr' L i carriage return. C th b ph nh. ìcrnl' Dch carriage return thnh newline. C th b ph nh. ìxon' Hot ha/ Cho php (Enable) iu khin dng XON/XOFF (XON/XOFF flow control) ( l, `CTRL-S'/`CTRL-Q'). C th b ph nh. ìxoff' `tandem' Hot ha/ Cho php (Enable) vic gi k t `dng' (`stop' character) khi vng m u vo h thng (system input buffer) gn nh y, v k t `bt u' (`start') khi n tr nn li gn nh rng. C th b ph nh. ìuclc' Dch cc k t in hoa thnh in thng. Khng phi POSIX. C th b ph nh. ìxany' Cho php bt k k t no khi ng li (restart) u ra (ch k t khi ng (start character) nu b ph nh). Khng phi POSIX. C th b ph nh. ìmaxbel' Hot ha/ Cho php (Enable) vic pht ting bp (beeping) v vic khng xa sch (not flushing) vng m u vo (input buffer) nu mt k t n khi vng m u vo y. Khng phi POSIX. CTrang 209/369


th b ph nh. File: coreutils.info, Node: Output, Next: Local, Prev: Input, Up: stty invocation 19.2.3 Cc t nh u ra ---------------------Cc tham s ny ch r cc vn hnh lin quan n u ra. òpost' Hu x l (Postprocess) u ra. C th b ph nh. òlcuc' Dch cc k t in thng thnh in hoa. Khng phi POSIX. C th b ph nh. òcrnl' Dch carriage return thnh newline. Khng phi POSIX. C th b ph nh. ònlcr' Dch newline thnh carriage return-newline. Khng phi POSIX. C th b ph nh. ònocr' Khng in cc carriage return ct u tin. Khng phi POSIX. C th b ph nh. ònlret' Newline thc hin mt carriage return (Newline performs a carriage return). Khng phi POSIX. C th b ph nh. òfill' Dng cc k t in y (s nhi m) (fill (padding) characters) thay v vic nh thi cho cc tr hon (timing for delays). Khng phi POSIX. C th b ph nh. òfdel' Dng cc k t xa (delete characters) cho s in y (for fill) thay v cc k t rng (null characters). Khng phi POSIX. C th b ph nh. `nl1'Trang 210/369


`nl0' Phong cch tr hon newline (Newline delay style). Khng phi POSIX. `cr3' `cr2' `cr1' `cr0' Phong cch tr hon carriage return (Carriage return delay style). Khng phi POSIX. `tab3' `tab2' `tab1' `tab0' Phong cch tr hon tab ngang (Horrizontal tab delay style). Khng phi POSIX. `bs1' `bs0' Phong cch tr hon xa li (Backspace delay style). Khng phi POSIX. `vt1' `vt0' Phong cch tr hon tab dc (Vertical tab delay style). Khng phi POSIX. `ff1' `ff0' Phong cch tr hon form feed (Form feed delay style). Khng phi POSIX. File: coreutils.info, Node: Local, Next: Combination, Prev: Output, Up: stty invocation 19.2.4 Cc t nh cc b --------------------ìsig' Hot ha/ Cho php (Enable) cc k t c bit ìnterrupt' (ngt), `quit' (thot), v `suspend' (treo). C th b ph nh/ c php b ph nh (May be negated). ìcanon'Trang 211/369


Hot ha/ Cho php (Enable) cc k t c bit èrase' (xa), `kill' (git, hy), `werase' (?), v `rprnt' (?). C th b ph nh. ìexten' Hot ha/ Cho php (Enable) cc k t c bit khng phi POSIX. C th b ph nh. ècho' Di li/ Vng li/ Lp li (Echo) cc k t u vo. C th b ph nh. èchoe' `crterase' Echo cc k t èrase' nh backspace-space-backspace (xa li- du cch- xa li). C th b ph nh. èchok' Echo mt newline sau mt k t `kill'. C th b ph nh. èchonl' Echo newline ngay c nu khng c vic echo cc k t khc. C th b ph nh. `noflsh' Bt kh ha (Disable) vic xa sch/ gii sch (flushing) sau cc k t c bit ìnterrupt' v `quit'. C th b ph nh. `xcase' Hot ha/ Cho php (Enable) u vo v u ra ca cc k t in hoa bng cch t trc cc th tng ng in thng ca chng bng `\', khi ìcanon' c t nh. Khng phi POSIX. C th b ph nh. `tostop' Dng cc cng vic nn sau (background jobs) m c vit vo thit b u cui. Khng phi POSIX. C th b ph nh. èchoprt' `prterase' Echo theo chiu ngc cc k t b xa (Echo erased characters backward), gia `\' v `/'. Khng phi POSIX. C th b ph nh.Trang 212/369


èchoctl' `ctlecho' Echo cc k t iu khin trong s ghi k hiu m (hat notation) (`^C') thay v kiu nguyn vn. Khng phi POSIX. C th b ph nh. èchoke' `crtkill' Echo k t c bit `kill' bng cch xa (erasing) mi k t trn dng nh c ch bi cc t nh èchoprt' v èchoe', thay v bi cc t nh èchoctl' v èchok'. Khng phi POSIX. C th b ph nh. File: coreutils.info, Node: Combination, Next: Characters, Prev: Local, Up: stty invocation 19.2.5 Cc t nh t hp/ kt hp (Combination settings) --------------------------Cc t nh t hp: èvenp' `parity' Ging nh `parenb -parodd cs7'. C th b ph nh. Nu b ph nh, ging nh `-parenb cs8'. òddp' Ging nh `parenb parodd cs7'. C th b ph nh. Nu b ph nh, ging nh `-parenb cs8'. `nl' Ging nh `-icrnl -onlcr'. C th b ph nh. Nu b ph nh, ging nh ìcrnl -inlcr -igncr onlcr -ocrnl -onlret'. èk' Ti t nh cc k t c bit èrase' v `kill' v cc gi tr mc nh ca chng. `sane' Ging nh: cread -ignbrk brkint -inlcr -igncr icrnl -ixoff -iuclc -ixany imaxbel opost -olcuc -ocrnl onlcrTrang 213/369


-onocr -onlret -ofill -ofdel nl0 cr0 tab0 bs0 vt0 ff0 isig icanon iexten echo echoe echok -echonl -noflsh -xcase -tostop -echoprt echoctl echoke v cng t nh tt c cc k t c bit v cc gi tr mc nh ca chng. `cooked' Ging nh `brkint ignpar istrip icrnl ixon opost isig icanon', cng thm t nh cc k t èof' (Nd: "end of file"="phn kt ca tp tin") v èol' (Nd: "end of line"="phn kt ca dng") v cc gi tr mc nh ca chng nu chng ging nh cc k t `min' v `time'. C th b ph nh. Nu b ph nh, ging nh `raw'. `raw' Ging nh: -ignbrk -brkint -ignpar -parmrk -inpck -istrip -inlcr -igncr -icrnl -ixon -ixoff -iuclc -ixany -imaxbel -opost -isig -icanon -xcase min 1 time 0 C th b ph nh. Nu b ph nh, ging nh `cooked'. `cbreak' Ging nh `-icanon'. C th b ph nh. Nu b ph nh, ging nh ìcanon'. `pass8' Ging nh `-parenb -istrip cs8'. C th b ph nh. Nu b ph nh, ging nh `parenb istrip cs7'. `litout' Ging nh `-parenb -istrip -opost cs8'. C th b ph nh. Nu b ph nh, ging nh `parenb istrip opost cs7'. `decctlq' Ging nh `-ixany'. Khng phi POSIX. C th b ph nh. `tabs' Ging nh `tab0'. Khng phi POSIX. C th b ph nh. Nu b ph nh, ging nh `tab3'. `lcase' `LCASE' Ging nh `xcase iuclc olcuc'. Khng phi POSIX. C th b ph nh.Trang 214/369


`crt' Ging nh èchoe echoctl echoke'. `dec' Ging nh èchoe echoctl echoke -ixany intr ^C erase ^? kill C-u'. File: coreutils.info, Node: Characters, Next: Special, Prev: Combination, Up: stty invocation 19.2.6 Cc k t c bit ------------------------Cc gi tr mc nh ca cc k t c bit thay i gia cc h thng (vary from system to system). Chng c t nh vi c php `TN GI_TR' (`name value'), trong cc tn c lit k bn di v gi tr c th c cho hoc theo nguyn vn, trong s ghi k hiu m (`^C'), hoc nh mt s nguyn m c th bt u vi `0x' ch ra thp lc phn, `0' ch ra bt phn, hay bt k ch s khc no ch ra thp phn. Cho stty GNU, vic cho mt gi tr `^-' hay ùndef' s bt kh ha k t c bit . (Ci ny bt tng thch vi `stty' Ultrix, m dng mt gi tr ù' bt kh ha mt k t c bit. `stty' GNU x l mt gi tr ù' nh bt k ci khc no, y l (namely) t nh k t c bit v .) ìntr' Gi (Send) mt tn hiu ngt (interrupt signal). `quit' Gi mt tn hiu thot (quit signal). èrase' Xa k t cui cng m c nh (my) vo (Erase the last character typed). `kill' Xa dng hin ti. èof' Gi mt end of file (chm dt u vo (terminate the input)).

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èol' Chm dt dng (End the line). èol2' Thay th k t chm dt dng (Alternate character to end the line). Khng phi POSIX. `swtch' Chuyn (Switch) n mt lp h v (shell layer) khc. Khng phi POSIX. `start' Ti khi ng u ra sau khi dng n. `stop' Dng u ra. `susp' Gi (Send) mt tn hiu dng thit b u cui (terminal stop signal). `dsusp' Gi (Send) mt tn hiu dng thit b u cui sau khi xa sch/ gii sch (flushing) u vo. Khng phi POSIX. `rprnt' V li (Redraw) dng hin ti. Khng phi POSIX. `werase' Xa (Erase) t (word) cui cng m c nh my vo. Khng phi POSIX. `lnext' Nhp (Enter) nguyn vn k t k tip m c nh my (Enter the next character typed literally), ngay c nu n l mt k t c bit. Khng phi POSIX. File: coreutils.info, Node: Special, Prev: Characters, Up: stty invocation 19.2.7 Cc t nh c bit -----------------------

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`min N' t nh s ti thiu ca cc k t m s tha mt s c cho n khi gi tr thi gian mn hn, khi `-icanon' c t nh. `time N' t nh s cc phn mi ca mt giy trc khi nhng s c mn hn (before reads time out) nu s ti thiu ca cc k t cha c c/ cha c c xong (have not been read), khi `-icanon' c t nh. ìspeed N' t nh tc u vo (input speed) N. òspeed N' t nh tc u ra (output speed) N. `rows N' Ni cho trnh iu khin nhn tty (tty kernel driver) rng thit b u cui c N dng. Khng phi POSIX. `cols N' `columns N' Ni cho nhn (the kernel) rng thit b u cui c N ct. Khng phi POSIX. `size' In s cc dng v cc ct m nhn ngh rng thit b u cui c. (Cc h thng m khng h tr cc dng v cc ct trong nhn th tiu biu dng cc bin mi trng `LINES' (Nd: S_DNG) v `COLUMNS' (Nd: S_CT) thay vo; tuy nhin, `stty' GNU khng bit bt k ci g v chng.) Khng phi POSIX. `line N' Dng k cng ng dy/ dng N (line discipline N). Khng phi POSIX. `speed' In tc thit b u cui (terminal speed). (Nd: cc t "speed", "rate" d gy lm ln v u c dch l "tc ", tuy nhin c l "rate" gn vi ngha "tn s" hn)Trang 217/369


`N' t nh cc tc u vo v u ra N. N c th l mt trong: 0 50 75 110 134 134.5 (Nd: du "." y ng ngha vi du "," trong cch ghi s thc ca ting Vit/ Php) 150 200 300 600 1200 1800 2400 4800 9600 19200 38400 èxta' èxtb'. èxta' ging nh 19200; èxtb' cng l 38400. 0 treo (hangs up) ng dy (the line) nu `-clocal' c t nh. File: coreutils.info, Node: printenv invocation, Next: tty invocation, Prev: stty invocation, Up: Working context 19.3 `printenv': In tt c hay vi bin mi trng ======================================================== `printenv' in cc gi tr bin mi trng. Tm tt: printenv [TY_CHN] [BIN]... Nu khng c cc BIN (VARIABLEs) no c ch r, `printenv' in gi tr ca mi bin mi trng. Nu khng, n in gi tr ca mi BIN m c t nh, v khng c g c cho nhng ci m khng c t nh. Cc ty chn duy nht l mt `--help' hay `--version' n c. *Note Common options:: (Cc ty chn chung). Tnh trng thot: 0 nu tt c cc bin m c ch r c tm thy 1 nu t nht mt bin c ch r khng c tm thy 2 nu mt li vit (write error) xy ra File: coreutils.info, Node: tty invocation, Prev: printenv invocation, Up: Working context 19.4 `tty': In tn tp tin ca thit b u cui ln (on) u vo chun ========================================================= `tty' in tn tp tin ca thit b u cui m c ni vo u vo chun ca n. N in `not a tty' (Nd: `khng phi l mt tty') nu u vo chun khng phi l mt thit b u cui. Tm tt:Trang 218/369


tty [TY_CHN]... Chng trnh chp nhn ty chn sau. Cng hy xem *Note Common options:: (Cc ty chn chung). `-s' `--silent' `--quiet' Khng in g c; ch tr v mt tnh trng thot.

Tnh trng thot: 0 nu u vo chun l mt thit b u cui 1 nu u vo chun khng l mt thit b u cui 2 nu cc tham s khng ng c cho (if given incorrect arguments) 3 nu mt li vit xy ra File: coreutils.info, Node: User information, Next: System context, Prev: Working context, Up: Top 20 Thng tin ngi dng ******************* Phn (section) ny m t cc lnh m in thng tin lin quan n ngi dng: logins, groups, v cn na (so forth). * Menu: * id invocation:: (triu gi id) In uid v gid thc v c hiu lc (real and effective uid and gid). * logname invocation:: (triu gi logname) In tn ng nhp hin ti (current login name). * whoami invocation:: (triu gi whoami) In id ngi dng c hiu lc (effective user id). * groups invocation:: (triu gi groups) In cc tn nhm m mt ngi dng trong . * users invocation:: (triu gi users) In cc tn ng nhp ca cc ngi dng m hin (c) ng nhp (login names of users currently logged in). * who invocation:: (triu gi who) In ai hin c ng nhp (who is currently logged in). File: coreutils.info, Node: id invocation, Next: logname invocation, Up: User informationTrang 219/369


20.1 ìd': In uid v gid thc v c hiu lc =============================================== ìd' in thng tin v ngi dng c cho, hay tin trnh m chy n (or the process running it) nu khng c ngi dng no c ch r. Tm tt: id [TY_CHN]... [TN_NGI_DNG] Theo mc nh, n in id ngi dng thc, id nhm thc, id ngi dng c hiu lc nu khc vi id ngi dng thc, id nhm c hiu lc nu khc vi id nhm thc, v cc id nhm b sung (supplemental group ids). Mi trong s cc gi tr s ny c i u bi mt chui nh danh (identifying string) v c theo sau bi tn ngi dng hay nhm tng ng trong cc du ngoc n (parentheses). Cc ty chn lm cho ìd' in ch thnh phn/ (mt) phn ca thng tin trn (only part of the above information). Cng hy xem *Note Common options:: (Cc ty chn chung). `-g' `--group' In ch id nhm. `-G' `--groups' In ch cc nhm b sung (supplementary groups). `-n' `--name' In tn ngi dng hay nhm thay v s ID. i hi `-u', `-g', hay `-G'. `-r' `--real' In id ngi dng hay nhm thc, thay v c hiu lc. i hi `-u', `-g', hay `-G'. `-u' `--user'Trang 220/369

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