You could use negative lookahead. An example:

use strict;
use warnings;

my @lines = <DATA>;
my $data;
foreach $data (@lines) {
    if($data =~ /sometext (?!not)\w* endtext/) {
        print "$data passed \n";
    }
}

__DATA__
sometext not endtext
sometext positive endtext

[download]

outputs

sometext positive endtext
 passed

[download]

In reply to Re: regex: something...(!something)...something by olus
in thread regex: something...(!something)...something by aaaone

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