Upload
hiroko-boyer
View
20
Download
0
Tags:
Embed Size (px)
DESCRIPTION
Chapter 12. Redirection and Pipes. Figure 12.1 Standard files and file descriptors: (a) file descriptors (b) semantics of a command execution. Figure 12.2 Input redirection: (a) file descriptors and standard files for ‘command’ (b) semantics of input redirection. - PowerPoint PPT Presentation
Citation preview
Figure 12.1 Standard files and file descriptors:(a) file descriptors(b) semantics of a command execution
Figure 12.2 Input redirection:(a) file descriptors and standard files for
‘command’(b) semantics of input redirection
Figure 12.3 Output redirection: (a) file descriptors and standard files for command’ (b) semantics of output redirection
Figure 12.3 Output redirection:(a) file descriptors and standard files for
‘command’(b) semantics of output redirection
Figure 12.6 Error redirection:(a) file descriptors and standard files for
‘command’(b) semantics of error redirection
Figure 12.6 Error redirection:(a) file descriptors and standard files for
‘command’(b) semantics of error redirection
Figure 12.8 Error redirection:(a) file descriptors and standard files(b) semantics of the commands
cat lab1 lab2 lab3 1> cat.output.errors 2>&1 cat lab1 lab2 lab3 2> cat.output.errors 1>&2
Figure 12.8 Error redirection:(a) file descriptors and standard files(b) semantics of the commands
cat lab1 lab2 lab3 1> cat.output.errors 2>&1cat lab1 lab2 lab3 2> cat.output.errors 1>&2
Figure 12.9 Output and error redirection:(a) file descriptors and standard files for the cat command(b) standard files after cat lab1 lab2 lab3 2>&1
with no change in stdout and stderr(c) standard files after cat lab1 lab2 lab3 2>&1 1>
cat.output.errors(d) command semantics
Figure 12.9 Output and error redirection:(a) file descriptors and standard files for the cat command(b) standard files after cat lab1 lab2 lab3 2>&1
with no change in stdout and stderr(c) standard files after cat lab1 lab2 lab3 2>&1 1>
cat.output.errors(d) command semantics
Figure 12.15 The semantics of the commandrsh server cat ~/research/pvm/datafile.server | diff
datafile -
noclobber option
set -o noclobberDisables the overwriting of existing files
set +o noclobber• Disables the overwriting of existing files
Figure 12.16 The semantics of the command cat names students | grep “John Doe” | tee file1
file2 | wc -l
Figure 12.17 Step-by-step semantics of the command
(find ~ -name foo -print > foo.paths) >& error.log
Figure 12.17 Step-by-step semantics of the command
(find ~ -name foo -print > foo.paths) >& error.log