Automatically Rewrite Shebang Line on Multiple Files

spickles has asked for the wisdom of the Perl Monks concerning the following question:

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Re: Automatically Rewrite Shebang Line on Multiple Files by samtregar (Abbot) on Feb 11, 2009 at 21:39 UTC
This is very easy if you've got cygwin to give you a working shell, find and xargs. For example, to change from /usr/bin/perl to /usr/local/bin/perl I'd do something like (untested): `find -name '.pl' -o -name '.cgi' \| xargs perl -pi -e "s{^#!/usr/bin/perl}{#!/usr/local/bin/perl}"` The -pi command-line switch tells Perl to do in-place editing and the -e specifies the code to on each line. If your filenames might have spaces in them you can add -print0 to the find call and -0 to the xargs call before perl. If you want to do it all in Perl can use File::Find or something similar to find the files for you. -sam	[reply] [d/l]
Re^2: Automatically Rewrite Shebang Line on Multiple Files by ikegami (Patriarch) on Feb 11, 2009 at 22:08 UTC
`for %q in (.cgi .pl) do ( perl -pi.bak -e"s{^#!/usr/bin/perl}{#!/usr/local/bin/perl}" "%q" )` [download] Change `for` to `for /r` for a recursive solution. Update: Simplified solution	[reply] [d/l] [select]
Re^3: Automatically Rewrite Shebang Line on Multiple Files by spickles (Scribe) on Feb 16, 2009 at 22:22 UTC
Your solution with a for loop has the word perl within it. Is this a script in a language other than perl, or is there some significance to the use of "perl -pi.bak"? I'm not familiar with cygwin - the last time I tried to install it something didn't work right. Regards, Scott	[reply]
Re^4: Automatically Rewrite Shebang Line on Multiple Files by ikegami (Patriarch) on Feb 16, 2009 at 23:30 UTC
Re^2: Automatically Rewrite Shebang Line on Multiple Files by linuxer (Curate) on Feb 11, 2009 at 21:53 UTC
Hi, possibly just a typo, the shebang starts with `#!`, not with `!#`.	[reply] [d/l] [select]
Re^3: Automatically Rewrite Shebang Line on Multiple Files by samtregar (Abbot) on Feb 11, 2009 at 22:07 UTC
Thanks - there's probably other errors. I usually have to play with a one-liner like this before it actually works. -sam	[reply]
Re: Automatically Rewrite Shebang Line on Multiple Files by linuxer (Curate) on Feb 11, 2009 at 22:28 UTC
Non Perl solution; tested on linux; I think this should be usable in cygwin as well: `find . -iname ".pl" -o -iname ".cgi" \| xargs sed -i.bac -e '1s"^#!.\+$"#! /usr/bin/perl"'` Udate added address `1` to sed expression, so only first line is examined/changed	[reply] [d/l] [select]
Re: Automatically Rewrite Shebang Line on Multiple Files by repellent (Priest) on Feb 12, 2009 at 06:19 UTC
I'd just like to point out that only the first line is of significance for a shebang line. Hence, performing a search-and-replace for lines `$. > 1` is not necessary unless... unless you have script-embedded shebangs?!	[reply] [d/l]