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Automatically Rewrite Shebang Line on Multiple Files

by spickles (Scribe)
on Feb 11, 2009 at 21:35 UTC ( #743170=perlquestion: print w/replies, xml ) Need Help??

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

Before I write my own script, I was wondering if anyone has already written a script to parse a directory looking for .pl and .cgi files and change the shebang line? I've got an installation of xampp and perl that I want to move from my c:\ drive to a portable drive. So I was thinking I would parse the files in a directory that have a shebang line and re-write it to point to the new location.

Regards,
Scott
  • Comment on Automatically Rewrite Shebang Line on Multiple Files

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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

      for %q in (*.cgi *.pl) do ( perl -pi.bak -e"s{^#!/usr/bin/perl}{#!/usr/local/bin/perl}" "%q" )

      Change for to for /r for a recursive solution.

      Update: Simplified solution

        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

      Hi, possibly just a typo, the shebang starts with #!, not with !#.

        Thanks - there's probably other errors. I usually have to play with a one-liner like this before it actually works.

        -sam

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
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?!

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