s/// treat rhs as regex

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

I wrote a program to do batch renaming on my mp3s. Tried, rather.


c:> rename.pl .*\.mp3 1(\d\d.*) 4$1
[download]

What I want is 103_track.mp3 to turn into 403_track.mp3. What I get is a file named 4$1. Thanks in advance.

my $inputMask = $ARGV[0];
my $regexSearch = $ARGV[1];
my $regexReplace= $ARGV[2];

my @files = <*.*>;

foreach my $file ( @files )
{
    if ( $file =~ /$inputMask/ )
    {
        my $oldname = $file;
        $file =~ s/$regexSearch/$regexReplace/;

        rename($oldname, $file) or die "$oldname to $file failed: $!";
        print "renamed $oldname to $file\n";
    }
}
[download]

Comment on s/// treat rhs as regex Select or Download Code

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Re: s/// treat rhs as regex by jwkrahn (Abbot) on Sep 07, 2008 at 06:30 UTC
This wheel has already been invented.	[reply]
Re: s/// treat rhs as regex by chromatic (Archbishop) on Sep 07, 2008 at 05:12 UTC
If you're sure that your shell doesn't expand metacharacters (that is, print `$regexReplace` to make sure it's sane), add the `/e` flag to your regexp.	[reply] [d/l] [select]
Re^2: s/// treat rhs as regex by AnomalousMonk (Archbishop) on Sep 07, 2008 at 10:14 UTC
Isn't a double-level of interpolation and eval required? `perl -wMstrict -e "my $regexSearch = $ARGV[0]; my $regexReplace = $ARGV[1]; my @strings = qw(103_foo 124_bar 109_quux); for my $string (@strings) { my $oldstring = $string; $string =~ s{ $regexSearch }{ qq{qq{$regexReplace}} }xmsee; print \"renamed $oldstring to $string \n\"; } " 1(\d\d.) 4$1 renamed 103_foo to 403_foo renamed 124_bar to 424_bar renamed 109_quux to 409_quux` [download] Update:* See also printig with variables in text and simple regular expression for further discussion.	[reply] [d/l]
Re^3: s/// treat rhs as regex by chuckH (Initiate) on Sep 11, 2008 at 01:53 UTC
Thank you very much. This is very helpful. I had examined the /e flag but didn't really grasp it. This plus your additions have been very elucidating.	[reply]