A piggy bank of commands, fixes, succinct reviews, some mini articles and technical opinions from a (mostly) Perl developer.

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Quick reference

STDERR and STDOUT appear in the wrong order when piping to a file

a Perl script - test.pl:

print "OUT 1\n";
print STDERR "ERR 2\n";
print "OUT 3\n";
print STDERR "ERR 4\n";
print "OUT 5\n";

Run the script, piping all output into a file:

perl test.pl &> file.log

cat file.log

ERR 2
ERR 4
OUT 1
OUT 3
OUT 5

Output is in the wrong order :(

Run it again using unbuffer:

unbuffer perl test.pl &> file.log

cat file.log

OUT 1
ERR 2
OUT 3
ERR 4
OUT 5

Output is in the correct order :)

(source)

Another way:

script -c 'perl ~/temp/stream.pl' file.log

cat file.log

(source)