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Lately there has been a tendency by command line tools to use fancy ANSI colors in their log output (for example, NPM and a host of nodejs based tools, rvm, docker, and a few other "modern" tools).

This makes it nice to read on the screen(*), but not so nice when you want to pipe the output to a log file or through a transport that does not handle ANSI well, like various remote execution tools and web based monitoring solutions. A lot of more mature tools at least had the decency to detect when the output is not a TTY and disable color, but not with those new fangled "user friendly" CLIs - which leaves me the try to get rid of the ANSI colors by piping the output through yet another process.

Sed-ing the output through s/\x1B\[[0-9]*\w//g seems to get the job done, but is there a cleaner approach then just copy pasting regular expressions into all of my scripts?

(*) at least until the the tool tries to display errors in dark red on your dark background terminal.

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    See: unix.stackexchange.com/questions/14684/… - unix.stackexchange.com/questions/111899/… stackoverflow.com/questions/17998978/… superuser.com/questions/380772/… -- Between 4+ questions over a span of 3 years across 3 sites we have only gotten answers to use a tool that does regex replacement/removal. I would guess there isn't anything better. – Zoredache Jan 14 '15 at 18:44
  • About the only thing that seems up for debate is which regex is the best for which situation. – Zoredache Jan 14 '15 at 18:45
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    is there a cleaner approach then just copy pasting regular expressions into all of my scripts? - Save your cleanup filter into a file called '/usr/local/bin/stripttycolor.sh` or something? That way you have the regex confined to a single location? – Zoredache Jan 14 '15 at 18:47
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    If you know that you will be writing the output to a file, the easiest thing to do (at least for NPM) is to run with the --no-color flag. Many other commands also have similar flags. – Moshe Katz Jan 15 '15 at 23:44
  • @MosheKatz: unfortunately not all commands do, for example bower. – Guss Jan 18 '15 at 13:34
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"ansifilter -p" might be useful to you...

It's in the Fedora repos; -p specifies plain output:

Name        : ansifilter
From repo   : updates
Summary     : ANSI terminal escape code converter
URL         : http://www.andre-simon.de/doku/ansifilter/ansifilter.php
License     : GPLv3+
Description : Ansifilter handles text files containing ANSI terminal escape codes.
            : The command sequences may be stripped or be interpreted to generate formatted
            : output (HTML, RTF, TeX, LaTeX, BBCode).
  • Works nicely, now I just need to get it packaged for Ubuntu :-) – Guss Jan 29 '15 at 13:58

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