http://www.perlmonks.org?node_id=443386


in reply to trim leading & trailing whitespace

Multiline, huh? You mean you want to trim every line independently? 
s/^[\t\ ]+//gm;
s/[\t\ ]+$//gm;

[download]
I don't use \s because I want to leave the newlines alone.

Replies are listed 'Best First'.
Re^2: trim leading & trailing whitespace
by thinker (Parson) on Mar 30, 2005 at 10:04 UTC

    Hi bart

    In the example I gave above,

     s/^\s*(.*?)\s*$/$1/gm

    the combination of the \m modifier, and the line anchors ^ and $ will ensure the newlines are left alone

    cheers

    thinker

[reply]
[d/l]
[select]
      $_ = "   no  \n   \n   \n    they    \n \n    won't     \n\n\n";
s/^\s*(.*?)\s*$/$1/gm;
print;

      [download]
      Result: 
      no
they
won't

      All blank lines are gone.

[reply]
[d/l]

        Hi bart,

        I see what you mean now. I thought you were suggesting it would remove the newline characters, not just the blank lines. Your way is more correct.

        cheers

        thinker

[reply]

        How about this:

        $_ = "   yes  \n   \n   \n    they    \n \n    will     \n\n\n";
s/^\s*?(?:\b(.*?)\s*?)?(\n)?$/$1$2/gm;
print;
__END__
% perl 443391.pl
yes


they

will

        [download]

        the lowliest monk

[reply]
[d/l]

In Section Seekers of Perl Wisdom