/tmp/demo2>cat three-os.pl #!/usr/bin/perl use strict; use warnings; open OUT,'>','unix.txt' or die "unix.txt: $!"; print OUT "line 1\x0Aline 2\x0Aline 3\x0A"; close OUT; open OUT,'>','oldmac.txt' or die "oldmac.txt: $!"; print OUT "line 1\x0Dline 2\x0Dline 3\x0D"; close OUT; open OUT,'>','windows.txt' or die "windows.txt: $!"; print OUT "line 1\x0D\x0Aline 2\x0D\x0Aline 3\x0D\x0A"; close OUT; exec "file *.txt" or die "exec failed: $!"; /tmp/demo2>perl three-os.pl oldmac.txt: ASCII text, with CR line terminators unix.txt: ASCII text windows.txt: ASCII text, with CRLF line terminators /tmp/demo2>