in reply to regexp exclude a string

Often two regexen are better than one. Possible strategy: search for the strings you want and set a flag. Also check for the string you don't want and forget about that file immediately if you find it. (You may optimize it not to try to match the "good ones" if one has already been found.) Print the name of the file if the flag is set.

Update: minimal example with glob. If you want/need to use File::Find or one of its relatives, then adapt as needed. Hack && improve at will.

# untested
FILE: for (glob '*.txt') {
    open my $fh, '<', $_ or
      die "$_: D'Oh! $!\n";
    my $found;
    while (<$fh>) {
        /green|red|blue/ and $found++ if !$found;
        next FILE if /green red blue/;
    }
    print if $found;  # $\ eq "\n"
}

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Or else if you trust in advance your files not to be huge, you may slurp in them all at once and simply

print if /green|red|blue/ and !/green red blue/;

But do not cargo cult that into a (bad) habit, slurping is generally not recommended.

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Re^2: regexp exclude a string
by Murcia (Monk) on Jan 19, 2006 at 14:34 UTC 
    #!/usr/bin/perl

FILE: for my $file (glob '*.txt') {
    open my $fh, '<', $file or die "$file: D'Oh! $!\n";
    while (<$fh>) {
        /(?=^(?:(?!green red blue).)*$).*?(green|red|blue)/i;
    do { 
        print "$file \n";
        next FILE;
    } if $1;
     }
   }

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[reply]
[d/l]

      (Any good reason why the shebang line is out of the code block?)

      If you find that more readable... but if you knew, then why did you need to ask in the first place? In the meanwhile your regex has grown complex enough and I tired enough not to even try and understand it. ;-)

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