Removing control chars (including console codes / colours) from script output

Question

I can use the "script" command to record an interactive session at the command line. However, this includes all control characters and colour codes. I can remove control characters (like backspace) with "col -b", but I can't find a simple way to remove the colour codes.

Note that I want to use the command line in the normal way, so don't want to disable colours there - I just want to remove them from the script output. Also, I know can play around and try find a regexp to fix things up, but I am hoping there is a simpler (and more reliable - what if there's a code I don't know about when I develop the regexp?) solution.

To show the problem:

spl62 tmp: script
Script started, file is typescript
spl62 lepl: ls
add-licence.sed  build-example.sh  commit-test         push-docs.sh
add-licence.sh   build.sh          delete-licence.sed  setup.py
asn              build-test.sh     delete-licence.sh   src
build-doc.sh     clean             doc-src             test.ini
spl62 lepl: exit
Script done, file is typescript
spl62 tmp: cat -v typescript
Script started on Thu 09 Jun 2011 09:47:27 AM CLT
spl62 lepl: ls^M
^[[0m^[[00madd-licence.sed^[[0m  ^[[00;32mbuild-example.sh^[[0m  ^[[00mcommit-test^[[0m         ^[[00;32mpush-docs.sh^[[0m^M
^[[00;32madd-licence.sh^[[0m   ^[[00;32mbuild.sh^[[0m          ^[[00mdelete-licence.sed^[[0m  ^[[00msetup.py^[[0m^M
^[[01;34masn^[[0m              ^[[00;32mbuild-test.sh^[[0m     ^[[00;32mdelete-licence.sh^[[0m   ^[[01;34msrc^[[0m^M
^[[00;32mbuild-doc.sh^[[0m     ^[[00;32mclean^[[0m             ^[[01;34mdoc-src^[[0m             ^[[00mtest.ini^[[0m^M
spl62 lepl: exit^M

Script done on Thu 09 Jun 2011 09:47:29 AM CLT
spl62 tmp: col -b < typescript 
Script started on Thu 09 Jun 2011 09:47:27 AM CLT
spl62 lepl: ls
0m00madd-licence.sed0m  00;32mbuild-example.sh0m  00mcommit-test0m         00;32mpush-docs.sh0m
00;32madd-licence.sh0m   00;32mbuild.sh0m          00mdelete-licence.sed0m  00msetup.py0m
01;34masn0m              00;32mbuild-test.sh0m     00;32mdelete-licence.sh0m   01;34msrc0m
00;32mbuild-doc.sh0m     00;32mclean0m             01;34mdoc-src0m             00mtest.ini0m
spl62 lepl: exit

Script done on Thu 09 Jun 2011 09:47:29 AM CLT

Answer 1

The following script should filter out all ANSI/VT100/xterm control sequences for (based on ctlseqs). Minimally tested, please report any under- or over-match.

#!/usr/bin/env perl
## uncolor — remove terminal escape sequences such as color changes
while (<>) {
    s/ \e[ #%()*+\-.\/]. |
       \e\[ [ -?]* [@-~] | # CSI ... Cmd
       \e\] .*? (?:\e\\|[\a\x9c]) | # OSC ... (ST|BEL)
       \e[P^_] .*? (?:\e\\|\x9c) | # (DCS|PM|APC) ... ST
       \e. //xg;
    print;
}

Known issues:

• Doesn't complain about malformed sequences. That's not what this script is for.
• Multi-line string arguments to DCS/PM/APC/OSC are not supported.
• Bytes in the range 128–159 may be parsed as control characters, though this is rarely used. Here's a version which parses non-ASCII control characters (this will mangle non-ASCII text in some encodings including UTF-8).

#!/usr/bin/env perl
## uncolor — remove terminal escape sequences such as color changes
while (<>) {
    s/ \e[ #%()*+\-.\/]. |
       (?:\e\[|\x9b) [ -?]* [@-~] | # CSI ... Cmd
       (?:\e\]|\x9d) .*? (?:\e\\|[\a\x9c]) | # OSC ... (ST|BEL)
       (?:\e[P^_]|[\x90\x9e\x9f]) .*? (?:\e\\|\x9c) | # (DCS|PM|APC) ... ST
       \e.|[\x80-\x9f] //xg;
    print;
}

Answer 2

Updating Gilles' answer to also remove carriage returns and do backspace-erasing of previous characters, which were both important to me for a typescript generated on Cygwin:

#!/usr/bin/perl

while (<>) {
  s/ \e[ #%()*+\-.\/]. |
    \r | # Remove extra carriage returns also
    (?:\e\[|\x9b) [ -?]* [@-~] | # CSI ... Cmd
    (?:\e\]|\x9d) .*? (?:\e\\|[\a\x9c]) | # OSC ... (ST|BEL)
    (?:\e[P^_]|[\x90\x9e\x9f]) .*? (?:\e\\|\x9c) | # (DCS|PM|APC) ... ST
    \e.|[\x80-\x9f] //xg;
    1 while s/[^\b][\b]//g;  # remove all non-backspace followed by backspace
  print;
}

Answer 3

There's an ansi2txt command in the colorized-logs package on Ubuntu. It removes ANSI color codes nicely, but it doesn't deal with things like progress bars produced by emitting ^H or ^M characters to overwrite text in place. col -b can deal with those, so for best results you can combine the two

cat typescript | ansi2txt | col -b

Answer 4

I would use sed in this case:

cat -v typescript | sed -e "s/\x1b\[.\{1,5\}m//g"

sed -e "s/search/replace/g" is standard stuff. The regex is explained as below:

• \x1b match the Escape preceeding the color code
• \[ matches the first open bracket
• .\{1,5\} matches 1 to 5 of any single character. Have to \ the curly braces to keep the shell from mangling them.
• m last character in regex - usually trails the color code.
• // empty string for what to replace everything with.
• g match it multiple times per line.

Answer 5

cat typescript | perl -pe 's/\e([^\[\]]|\[.*?[a-zA-Z]|\].*?\a)//g' | col -b > typescript-processed

Answer 6

# The "sed -r" trick does not work on every Linux, I still dunno why:
DECOLORIZE='eval sed "s,${END}\[[0-9;]*[m|K],,g"'

=> howto use:

<commands that type colored output> | ${DECOLORIZE}

tested on: - AIX 5.x / 6.1 / 7.1 - Linux Mandrake / Mandriva / SLES / Fedora - SunOS

Answer 7

I solved the problem by running scriptreplay in a screen and the dumping the scrollback buffer to a file.

The following expect script does this for you.

It has been tested for logfiles with up to 250.000 lines. In the working directory you need your scriptlog, a file called "time" with 10.000.000 times the line "1 10" in it, and the script. I needs the name of your scriptfile as command line argument, like ./name_of_script name_of_scriptlog.

#!/usr/bin/expect -f 

set logfile [lindex $argv 0]

if {$logfile == ""} {puts "Usage: ./script_to_readable.exp \$logfile."; exit}

set timestamp [clock format [clock sec] -format %Y-%m-%d,%H:%M:%S]
set pwd [exec pwd]
if {! [file exists ${pwd}/time]} {puts "ERROR: time file not found.\nYou need a file named time with 10.000.000 times the line \"1 10\" in the working directory for this script to work. Please provide it."; exit}
set wc [exec cat ${pwd}/$logfile | wc -l]
set height [ expr "$wc" + "100" ]
system cp $logfile ${logfile}.tmp
system echo $timestamp >> ${logfile}.tmp
set timeout -1
spawn screen -h $height -S $timestamp 
send "scriptreplay -t time -s ${logfile}.tmp 100000 2>/dev/null\r"
expect ${timestamp} 
send "\x01:hardcopy -h readablelog.${timestamp}\r"

send "exit\r"

system sed '/^$/d' readablelog.$timestamp >> readablelog2.$timestamp
system head -n-2 readablelog2.$timestamp >> ${logfile}.readable.$timestamp
system rm -f readablelog.$timestamp readablelog2.$timestamp ${logfile}.tmp

The time file can be generated by

for i in $(seq 1 10000000); do echo "1 10" >> time; done

Answer 8

I use

cat file | ansifilter

See https://gitlab.com/saalen/ansifilter.

Answer 9

I would prefer to use specialized tools to convert script output into plain text, which is constantly supported and well tested, over custom regexp. So this did job for me:

$ cat typescript | ansi2txt | col -bp > typescript.txt.bp    
$ cat -v typescript.txt.bp

script command captures into typescript file ansi2txt - converts ansi code with escapes like colorcodes, backspaces etc into regular text, however I found that couple escapes still left. col -bp - removed them completely.

I’ve tested this on latest Ubuntu disco, and it works.

Answer 10

Although the solutions given so far work nicely to remove the control sequences, however they also remove the formatting codes. The result is that the tables in the output are squished together. My requirement was just to be able to view and search in the session log files collected from the terminal. The solution that works best for me was using less -r.

less -r session.log

Answer 11

Found this question while looking for the a solution to the same problem. A little more digging and found this script over at Live Journal at this link. I worked perfectly for me. It's also a very good write up about this problem and how the solution works. Definitely worth a read. http://jdimpson.livejournal.com/7040.html

#!/usr/bin/perl -wp

# clean up control characters and other non-text detritus that shows up 
# when you run the "script" command.

BEGIN {
# xterm titlebar escape sequence
$xtermesc = "\x1b\x5d\x30\x3b";

# the occurence of a backspace event (e.g. cntrl H, cntrol W, or cntrl U)
$backspaceevent = "\x1b\\\x5b\x4b"; # note escaping of third character

# ANSI color escape sequence
$ansiesc = qr/\x1b\[[\d;]*?m/;

# technically, this is arrow-right. For some reason, being used against
# very long backspace jobs. I don't fully understand this, as evidenced
# by the fact that is off by one sometimes.
$bizarrebs = qr/\x1b\[C/;

# used as part of the xterm titlebar mechanism, or when
# a bell sounds, which might happen when you backspace too much.
$bell = "\x07"; # could use \a

$cr = "\x0d"; # could use \r

$backspace = "\x08"; # could use \b
}

s/$xtermesc.+?$bell//g;
s/[$cr$bell]//g;
s/${backspaceevent}//g;
s/$ansiesc//g;
while (s/(.)(?=$backspace)//) { s/$backspace//; } # frickin' sweet 
# For every ^H delete the character immediately left of it, then delete the ^H.
# Perl's RE's aren't R, so I wonder if I could do this in one expression.
while (s/(..)(?=$bizarrebs)//) { s/$bizarrebs//; }

Answer 12

I found that just using cat was all I needed to view the output of script in the terminal. This doesn't help when redirecting the output to another file, but does make the result readable, unlike cat -v, col -b, or a text editor.

To eliminate colors or save the results to a file, manually copy and paste the output from cat into a text editor, or into another cat command, i.e.:

cat > endResult << END
<paste_copied_text_here>
END

Answer 13

I use

env TERM=dumb SHELL=/bin/bash script

leaves you with a typescript file with a bunch of ^M but I just remove those

• with vi

  :1,$s/^M//g
  

  remembering to escape the ^M with ^V

• or just use

  dos2unix typescript
  

Answer 14

Following up on the last answer which uses tr and :cntrl: could we maybe do

sed "/^[[:cntrl:]]/d" output.txt

This seems to work for me because all lines generated by vi start with a control character. It happens to also strip out blank lines and lines that start with a tab, although that works for what I'm doing. Maybe there is a way to match any control character except for \n \m \t.

Maybe we can search for the particular control character, and it looks like all junk lines generated by vi start with what looks like ^[. hexdump tells me the first character is 1b, so this seems to work too

sed "/^\x1b/d" output.txt

This looks similar to an answer posted above, but it does not work properly because after running the command, some junk chars are already added to the command line as if the user had typed them.

Answer 15

tr - translate or delete characters

cat typescript | tr -d [[:cntrl:]]