1) Lookarounds aren't needed.

2) 

Here is a one-liner:

perl -pi -e '$_ = "#$_" if /^\s*Defaults    (requiretty|env_reset)\s*$
+/'

[download]

You match the spaces and then you keep them in the modified line--the op wants to remove the leading spaces (and possibly the trailing spaces?). That's why the people up there ^ were using lookarounds.

use strict;
use warnings;
use 5.010;
 
my $str =<<"ENDOFSTRING";
  Defaults    env_reset      
         Defaults    requiretty     
ENDOFSTRING
 
 
open(my $INPUT, '<', \$str)
  or die "Couldn't open for string io: $!";
 
while (my $line = <$INPUT>) {
    $line =~ s{ 
                   \s* 
                   (
                         Defaults
                         \s*
                         (env_reset | requiretty)
                   )
                   \s*
               }
               {#$1}xms;
 
    say "-->$line<--";
}
 
close $INPUT;

--output:--
-->#Defaults    env_reset<--
-->#Defaults    requiretty<--

[download]

In reply to Re: Perl search and replace by 7stud
in thread Perl search and replace by austin43

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