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Full Discussion: command line explanation
Top Forums Shell Programming and Scripting command line explanation Post 302277398 by goude on Friday 16th of January 2009 08:07:35 AM
Old 01-16-2009
command line explanation

Hello everyone,

I found this command line in a website:

perl -pi.bak -we's/\z/Your new line\n/ if $. == 2;' your_text_file.txt

With this command line you can insert a new line anywhere you want in a text without overwriting what's in it.

-p causes perl to assume a loop around your file so that you can process it.
i.bak creates a back up file
-w turns on warnings.
-e is the script you want to execute.

Does anyone know what s/\z/ is for?

Thanks a lot.
 

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RENAME(1)						 Perl Programmers Reference Guide						 RENAME(1)

NAME
rename - renames multiple files SYNOPSIS
rename [ -v ] [ -n ] [ -f ] perlexpr [ files ] DESCRIPTION
"rename" renames the filenames supplied according to the rule specified as the first argument. The perlexpr argument is a Perl expression which is expected to modify the $_ string in Perl for at least some of the filenames specified. If a given filename is not modified by the expression, it will not be renamed. If no filenames are given on the command line, filenames will be read via standard input. For example, to rename all files matching "*.bak" to strip the extension, you might say rename 's/.bak$//' *.bak To translate uppercase names to lower, you'd use rename 'y/A-Z/a-z/' * OPTIONS
-v, --verbose Verbose: print names of files successfully renamed. -n, --no-act No Action: show what files would have been renamed. -f, --force Force: overwrite existing files. ENVIRONMENT
No environment variables are used. AUTHOR
Larry Wall SEE ALSO
mv(1), perl(1) DIAGNOSTICS
If you give an invalid Perl expression you'll get a syntax error. BUGS
The original "rename" did not check for the existence of target filenames, so had to be used with care. I hope I've fixed that (Robin Barker). perl v5.14.2 2014-09-26 RENAME(1)
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