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ITU UNIX Operating SystemAssignment #1

Practice creating and using Basic Scripts

1. A shell is !th a c!mmand line interpreter and a pr!gramminglanguage. "plain the di$$erence et%een the $!ll!%ing shells&

bash cshperl ksh

In y!ur h!me direct!ry' ma(e a in sudirect!ry )i$ it d!esn*t eist+

mkdir bin

,! int! that sudirect!ry cd bin

-. In y!ur in sudirect!ry' create the $!ll!%ing $ile named commandsusing "macs !r i )!r any tet edit!r+

# a simple shell scriptcaldatewho

/. Sae the $ile' 0eae the edit!r' try t! run the script commandshat happens2

3. 4a(e the script eecutale chmod ug+x commands

5. N!% try t! run the script commands

6. 4a(e sure the ash shell is al%ays eecuted %hen y!u run thisscript

,! ac( int! the "dit!r and add this statement t! the t!p !$ the $ile

#!/bin/bash

POSITIONA0 PA7A4"T"7S

hen y!u call a shell script %ith arguments' y!u can access them insidethe script %ith the special ariales

$1, $2,etc.. $*re$ers t! all !$ the arguments

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The ariale $0re$ers t! the name !$ the calling pr!gram !r script.

8. 9reate the $!ll!%ing script called echoargs

#!/bin/bash# illustrate the use o positional parametersecho $0 $1 $2 $" $ $ $% $& $' $(

:. 4a(e the script eecutale and try it !ut %ith this c!mmand& echoargs )o be or not to be

;. 9hange the script s! it l!!(s li(e this&

#!/bin/bash# illustrate the use o positional parameters, user deined# ariables and the read commandecho what is our name-read nameecho .well, $name, ou tped $# arguments.echo .$*.

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echo .a $1.echo .ate $" $2 $%.

15. Sae the $ile' ma(e it eecutale' run the $ile

APP0I9ATION&

The %c )?%!rd c!unt?+ $ilters and c!unts the %!rds' lines' and charactersin a $ile. @!r eample' try running %c !n the setdate $ile y!u ust made&

$ wc setdate% 2" 12 setdate

)& %hat p!siti!nal parameter is the $ilename in the !utput2+

The !utput tells us there are 6 lines' -/ %!rds and 1-3 characters. T!

impr!e !n %c' y!u are g!ing t! ma(e a ne% script called mwc' %hich%ill pr!ide a m!di$ied !utput laeling each p!rti!n s! it is m!rereadale. The !utput !$ y!ur script mwc' used in the $!ll!%ingc!mmandmwc setdate sh!uld read

setdate count3 lines % words 2" characters 12

T! d! this' create the script mwcusing the $!ll!%ing plan&

1+ Select the ash shell.-+ 7un %c !n the C1 p!siti!nal parameter and capture the !utput usingset/+ Print the $ilename )C3+3+ Print the numer !$ lines )C1+' numer !$ %!rds )C-+ and numer !$characters )C/+ using appr!priate laels.5+ Use y!ur script setdate as a m!del $!r this pr!lem.6+ Paste y!ur $inished script el!%.