Perl One-Liners

Appendix C. Perl1Line.Txt

As I was writing this book, I compiled all the one-liners in a file called perl1line.txt. This appendix is that file. It comes in very handy when you need to quickly look up a one-liner. You can just open perl1line.txt in a text editor and search for the action you want to perform. The latest version of this file can always be found at http://www.catonmat.net/download/perl1line.txt.

C.1 Spacing

Double-space a file

perl -pe '$\ = "\n"'
perl -pe 'BEGIN { $\ = "\n" }'
perl -pe '$_ .= "\n"'
perl -pe 's/$/\n/'
perl -nE 'say'

Double-space a file, excluding the blank lines

perl -pe '$_ .= "\n" unless /^$/'
perl -pe '$_ .= "\n" if /\S/'

Triple-space a file

perl -pe '$\ = "\n\n"'
perl -pe '$_ .= "\n\n"'
perl -pe 's/$/\n\n/'

N-space a ...