Terminal Colors – How to Clean stdout/stderr Color Output

You'd think there'd be a utility for that, but I couldn't find it. However, this Perl one-liner should do the trick:

perl -pe 's/\e\[?.*?[\@-~]//g'

Example:

$ command-that-produces-colored-output | perl -pe 's/\e\[?.*?[\@-~]//g' > outfile

Or, if you want a script you can save as stripcolorcodes:

#! /usr/bin/perl

use strict;
use warnings;

while (<>) {
  s/\e\[?.*?[\@-~]//g; # Strip ANSI escape codes
  print;
}

If you want to strip only color codes, and leave any other ANSI codes (like cursor movement) alone, use

s/\e\[[\d;]*m//g;

instead of the substitution I used above (which removes all ANSI escape codes).

This is a simple solution if you're willing to accept output just above the current prompt line.

bufferout () {
    local buffer
    while IFS= read -r line; do              # buffer stdin
        buffer="$buffer$line\n"
    done
    print -rn -- $terminfo[dl1]              # delete current line
    printf "$buffer"                         # print buffer
    kill -USR1 $$                            # send USR1 when done
}

TRAPUSR1 () {                                # USR1 signal handler
    zle -I                                   # invalidate prompt
    unhash -f TRAPUSR1 bufferout             # remove ourselves
}

./testout 2>&1 | bufferout &!                # run in background, disowned

When the job is done, the current prompt and input buffer will be removed and the entirety of the command's stdout and stderr will be printed.

Note that this assumes it will be run exactly once and removes itself afterwards. If you want to keep reusing this functionality in the same shell, remove the unhash -f line in TRAPUSR1.

This answer includes an improvement suggested by Clint Priest in the comments. Thanks!