Pipelines Post: 302109406

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Top Forums UNIX for Dummies Questions & Answers Pipelines Post 302109406 by Vn3050 on Monday 5th of March 2007 07:23:18 PM

03-05-2007

Registered User

Pipelines

Now before this thread gets closed, please be aware this is not classwork or homework, I am trying to learn unix by myself, and have come stuck below. So it is a pointless to close this thread, as I am trying to improve my unix by asking advice from people. That is what I assume a forum is for!

I am trying to work out how to complete this question, and after learning a bit more unix. i have written an answer to it. Can anyone check to see if it is correct and what improvements need to be made?

Write a pipeline that updates the content of a file (a file of your choice) by replacing all matches of the word �and' with the symbol �&' and by replacing the end of each line with the user login name. If the command completes successfully it should print �YES', otherwise it should print �NO'.

cat text.txt | sed -e s/and/$USER/g -e s/$/�&�/g | cat -> text.txt
&& echo yes || echo no

thanks
vish

Vn3050

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LEARN ABOUT DEBIAN

rpl

RPL(1)							    BSD General Commands Manual 						    RPL(1)

NAME

     rpl -- replace strings in files

SYNOPSIS

     rpl [-LhiwbqvsRepfdt] [-xSUFFIX] <old_string> <new_string> <target_file ...>

DESCRIPTION

     Basic usage is to specify two strings and one or more filenames or directories on the command line.  The first string is the string to
     replace, and the second string is the replacement string.

     -h, --help
	     A short help text.

     -L, --license
	     Show the license and exit.

     -xSUFFIX
	     Search only files ending with SUFFIX, e.g.  ``.txt''.  May be specified multiple times.

     -i, --ignore-case
	     Ignore the case of old_string.

     -w, --whole-words
	     Make old_string match only on word boundaries.

     -b, --backup
	     Move the original files to filename~ before replacing them.

     -q, --quiet
	     Quiet mode.

     -v, --verbose
	     Verbose mode.

     -s, --dry-run
	     Simulation mode, no files are changed.

     -R, --recursive
	     Recurse into subdirectories.

     -e, --escape
	     Expand escape sequences in old_string and new_string.  Examples of escape sequences are '
' (new-line), '	' (tab), 'x42' (hexadec-
	     imal number 42), '33' (octal number 033).

     -p, --prompt
	     Prompt for confirmation before replacing each file.

     -f, --force
	     Ignore errors when trying to restore permissions and file ownership.

     -d, --keep-times
	     Keep modification times when replacing files.

     -t, --use-tmpdir
	     Use a temporary directory for storing temporary files, usually the value of the environment variable TMPDIR.  The default is to put
	     temporary files in the same directory as the file being modified.

     -a, --all
	     Do not ignore files and directories starting with .

IMPLEMENTATION NOTES

     An effort has been made to make the program behave as much as the original rpl as necessary.  Where it has been possible to make improve-
     ments, improvements have been made.  This implementation lacks many of the bugs in the original.

EXAMPLES

     Replace all occurences of ``F'' (on word boundaries) with ``A'' in all text files under the grades/ directory:
	   $ rpl -Rwd -x'.txt' 'F' 'A' grades/

SEE ALSO

     find(1), sed(1).

HISTORY

     This program was written for Debian as a free replacement for the non-free rpl program by Joe Laffey.

AUTHORS

     Goran Weinholt <weinholt@debian.org>.

Debian								   July 31, 2005							    Debian