Gfrktyl

Examining the output from

perl -e 'use Term::ANSIColor; print color "white"; print "ABCn"; print color "reset";'

in a text editor (e.g., vi) shows the following:

^[[37mABC

^[[0m

How would one remove the ANSI color codes from the output file? I suppose the best way would be to pipe the output through a stream editor of sorts.

The following does not work

perl -e 'use Term::ANSIColor; print color "white"; print "ABCn"; print color "reset";' | perl -pe 's/^[[37m//g' | perl -pe 's/^[[0m//g'

The characters ^[[37m and ^[[0m are part of the ANSI Escape sequences (CSI codes).

See also the complete specifications.

Using sed

sed 's/x1b[[0-9;]*m//g'

• 
  x1b is the escape special character (same as x1B or '33`)


• 
  [ is the second character of the escape sequence


• 
  [0-9;]* is the color value(s)


• 
  m is the last character of the escape sequence

Example with OP's command line:
^{(OP = Original Poster)}

perl -e 'use Term::ANSIColor; print color "white"; print "ABCn"; print color "reset";' | 

sed 's/x1b[[0-9;]*m//g'

Tom Hale suggests to remove all other escape sequences using [a-zA-Z] instead just the letter m specific to color escape sequence. But [a-zA-Z] may be too wide and could remove too much. Michał Faleński and Miguel Mota proposes to remove only some escape sequences using [mGKH] and [mGKF] respectively.

sed 's/x1b[[0-9;]*m//g'        # Remove color sequences only

sed 's/x1b[[0-9;]*[a-zA-Z]//g' # Remove all escape sequences

sed 's/x1b[[0-9;]*[mGKH]//g'   # Remove color and move sequences

sed 's/x1b[[0-9;]*[mGKF]//g'   # Remove color and move sequences



Last escape

sequence

character   Purpose

---------   -------------------------------

m           Color

G           Horizontal cursor move

K           Horizontal deletion

H           New cursor position

F           Move cursor to previous n lines

Using perl

The version of sed installed on some operating systems may be limited (e.g. MacOS X). The command perl has the advantage to be often more easily to install/update on more operating systems.

Choose your regex depending on how much commands you want to filter:

perl -pe 's/x1b[[0-9;]*m//g'        # Remove colors only

perl -pe 's/x1b[[0-9;]*[mG]//g'

perl -pe 's/x1b[[0-9;]*[mGKH]//g'

perl -pe 's/x1b[[0-9;]*[a-zA-Z]//g'

Example with OP's command line:

perl -e 'use Term::ANSIColor; print color "white"; print "ABCn"; print color "reset";' | 

perl -pe 's/x1b[[0-9;]*m//g'

Usage

As pointed out by Stuart Cardall's comment, this trick is used by the project Ultimate Nginx Bad Bot (almost 1000 stars) to clean up the email report ;-)

I have found out a better escape sequence remover.
Check this:

perl -pe 's/x1b[[0-9;]*[mG]//g'

What is displayed as ^[ is not ^ and [; it is the ASCII ESC character, produced by Esc or Ctrl[ (the ^ notation means the Ctrl key).

ESC is 0x1B hexadecimal or 033 octal, so you have to use x1B or 33 in your regexes:

perl -pe 's/33[37m//g; s/33[0m//g'



perl -pe 's/33[d*(;d*)*m//g'

If you prefer something simple you could use the strip-ansi module (Node.js required):

$ npm install --global strip-ansi-cli

Then use it like this:

$ strip-ansi < colors.o

Or just pass in a string:

$ strip-ansi '^[[37mABC^[[0m'

The "answered" question didn't work for me, so I created this regex instead to remove the escape sequences produced by the perl Term::ANSIColor module.

cat colors.o | perl -pe 's/x1b[[^m]+m//g;

Grawity's regex should work fine, but using +'s appears to work ok too.