#!/usr/bin/perl open my $oldout, ">&STDOUT" or die "Can't dup STDOUT: $!"; open OLDERR, ">&", \*STDERR or die "Can't dup STDERR: $!"; open STDOUT, '>', "foo.out" or die "Can't redirect STDOUT: $!"; open STDERR, ">&STDOUT" or die "Can't dup STDOUT: $!"; select STDERR; $| = 1; # make unbuffered select STDOUT; $| = 1; # make unbuffered print STDOUT "stdout 1\n"; # this works for print STDERR "stderr 1\n"; # subprocesses too open STDOUT, ">&", $oldout or die "Can't dup \$oldout: $!"; open STDERR, ">&OLDERR" or die "Can't dup OLDERR: $!"; print STDOUT "stdout 2\n"; print STDERR "stderr 2\n";