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Chapter 12

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.

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Chapter 12

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  1. Chapter 12 Redirection and Pipes

  2. Figure 12.1  Standard files and file descriptors: (a) file descriptors (b) semantics of a command execution

  3. Figure 12.2  Input redirection: (a) file descriptors and standard files for ‘command’ (b) semantics of input redirection

  4. Figure 12.3 Output redirection: (a) file descriptors and standard files for command’ (b) semantics of output redirection

  5. Figure 12.3 Output redirection: (a) file descriptors and standard files for ‘command’ (b) semantics of output redirection

  6. Figure 12.4 Semantics of command run on remote serverrsh server sort < datafile

  7. Figure 12.5  Combined use of input and output redirection

  8. Figure 12.6  Error redirection: (a) file descriptors and standard files for ‘command’ (b) semantics of error redirection

  9. Figure 12.6  Error redirection: (a) file descriptors and standard files for ‘command’ (b) semantics of error redirection

  10. Figure 12.7  Error & Output redirection: cat lab1 lab2 lab3 1> cat.output 2> cat.errors

  11. 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

  12. 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

  13. 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

  14. 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

  15. Figure 12.10 Redirecting stdin, stdout, and stderr in a single command

  16. Figure 12.11  The semantics of a pipeline with N commands

  17. Figure 12.12  The semantics of the commandls -l | more command

  18. Figure 12.13  The semantics of the commandgrep “John” < Students | lpr –Pspr

  19. Figure 12.14  The semantics ofegrep ‘A$’ < ee446.grades | sort > ee446.As.sorted

  20. Figure 12.15 The semantics of the commandrsh server cat ~/research/pvm/datafile.server | diff datafile -

  21. noclobber option set -o noclobber Disables the overwriting of existing files set +o noclobber • Disables the overwriting of existing files

  22. tee Command Syntax tee [options] file-list Reads input, echoes to stdin and all files in file-list

  23. Figure 12.16  The semantics of the command cat names students | grep “John Doe” | tee file1 file2 | wc -l

  24. Figure 12.17  Step-by-step semantics of the command(find ~ -name foo -print > foo.paths) >& error.log

  25. Figure 12.17  Step-by-step semantics of the command(find ~ -name foo -print > foo.paths) >& error.log

  26. Table 12.1 Redirection Operators and Their Meaning in Bash and TC Shells

  27. Table 12.1 Redirection Operators and Their Meaning in Bash and TC Shells

  28. Table 12.1 Redirection Operators and Their Meaning in Bash and TC Shells

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