That's fine, but I recommend avoiding $1, $2, etc. If you put the left-hand-side in a list context, a variable like $version can be assigned directly without fiddling with $1 as an intermediary. For most folks, $version is easier to understand than just $1.

Your if() statement is correct, a successful match will return a true/false value. However an assignment to $version like below will return a "defined" or "not defined" value which can also be used in an "if".

chomp if you like, but adding \s*$ includes \n in the regex (no need for chomp). chomp is "not expensive", but once we whip out the nuclear weapon of regex, asking it to throw away any trailing white space is no big deal. 

use strict;
use warnings;

while (my $line = <DATA>) 
{
    my ($version) = $line =~ /^[a-z-]+(\d.*)\s*$/; 
    print ">>$version<<\n" if $version;   
}
=PRINTS:
>>2.10<<
>>2.10.2-r1<<
>>2.10.5<<
=cut

__DATA__
mono-basic-2.10
mono-2.10.2-r1
mono-2.10.5

[download]

In reply to Re^2: regex behaves differently in split vs substitute? by Marshall
in thread regex behaves differently in split vs substitute? by raygun

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