[ ~/tmp ] $ cat spacey_text 1 12 23 32 21 1 a b c d e 1 blank: 2 blanks: 3 blanks: end_blanks [ ~/tmp ] $ perl -we 'use strict; { local $/ = ""; while (<>) { $_ =~ y/ / /s; print $_; } }' spacey_text 1 12 23 32 21 1 a b c d e 1 blank: 2 blanks: 3 blanks: end_blanks [ ~/tmp ] $