Color output in console
This page was created to consolidate colorization of CLI outputs.
Background
Escape sequences
The ANSI escape sequences define a way to put additional information into terminal output, and color is part of this "additional information". Throughout the years the range of terminal colors has been vastly expanded, from the initial eight colors to a full 24-bit truecolor.
The basic color encoding provides 8 normal-brightness colors and 8 brighter versions of these colors. Modern terminal emulators, including the Linux console itself, allows you to specify the precise RGB values that the colors translate to. This mode is supported by almost all terminal emulators.
With the advent of 256-color displays came the 256-color escape. The 256 colors are the 16 basic colors, the 216 RGB colors (laid out in a 6x6x6 cube), and 24 levels of greyscale. Except for the first 16 colors, the scheme is usually not customizable as it has a well-defined mapping to RGB. This mode is supported by most terminal emulators. (A minority of emulators use a similar but incompatible encoding with only 88 colors. You are very unlikely to use them in practice, but they will appear in the terminfo database.)
Less commonly supported is the truecolor mode, allowing one to use 16.7 million (224) colors in RGB (each value ranging from 0 to 255).
Termcap and terminfo
Termcap and terminfo, part of ncurses, are databases that provide information on the escape sequences terminals (usually specified by the TERM env-var) understand. The tput(1) and infocmp(1) commands can be used to access them from command-line.
Applications
diff
diffutils from version 3.4 includes the --color option (GNU mailing list).
$ alias diff='diff --color=auto'
grep
The --color=auto option enables color highlighting. Color codes are emitted only on standard output; not in pipes or redirection.
Color output in grep is also useful with regexp tasks.
Use an alias to permanently enable this option:
alias grep='grep --color=auto'
The GREP_COLORS variable is used to define colors, and it configures various parts of highlighting. To change the colors, find the needed ANSI escape sequence and apply it. See grep(1) § GREP COLORS for more information.
The -n option includes file line numbers in the output.
ip
ip(8) command from iproute2 supports colors with -c/-color option. When using the auto parameter, colored output will be enabled only when stdout is a terminal. iproute2 can be built with auto as the default, but such a change has been rejected by the Arch package maintainer.
You can use an alias to enable colored output, e.g.:
alias ip='ip -color=auto'
less
Environment variables
As with the #man case, we can tell less to emit colors when it is meaning to make bold text and other formatting effects.
Add the following lines to your shell configuration file:
export LESS='-R --use-color -Dd+r$Du+b$'
It will set red for bold and blue for underlined.
For more information about the --use-color and -D options, see less(1) § D or [1].
Reading from stdin
~/.bashrc or ~/.zshrc, as the below is based on export LESS='-R'
When you run a command and pipe its standard output (stdout) to less for a paged view (e.g. pacman -Qe | less), you may find that the output is no longer colored. This is usually because the program tries to detect if its stdout is an interactive terminal, in which case it prints colored text, and otherwise prints uncolored text. This is good behaviour when you want to redirect stdout to a file, e.g. pacman -Qe > pkglst-backup.txt, but less suited when you want to view output in less.
Some programs provide an option to disable the interactive tty detection:
# dmesg --color=always | less
In case that the program does not provide any similar option, it is possible to trick the program into thinking its stdout is an interactive terminal with the following utilities:
- ColorThis — Force colored output of a program by running it within a (group of) pty, support forwarding stdin.
-
stdoutisatty — A small program and a
LD_PRELOAD-able library that catches the isatty(3) function call.
- https://github.com/lilydjwg/stdoutisatty. || stdoutisatty
- Example:
stdoutisatty program | less
- unbuffer — A tclsh script comes with expect, it invokes desired program within a pty.
- http://expect.sourceforge.net/example/unbuffer.man.html[dead link 2024-07-30 ⓘ] || expect
- Example:
unbuffer program | less
Alternatively, using zpty module from zsh: [2]
~/.zshrc
zmodload zsh/zpty
pty() {
zpty pty-${UID} ${1+$@}
if [[ ! -t 1 ]];then
setopt local_traps
trap '' INT
fi
zpty -r pty-${UID}
zpty -d pty-${UID}
}
ptyless() {
pty $@ | less
}
Usage:
$ ptyless program
To pipe it to other pager (less in this example):
$ pty program | less
ls
The --color=auto option enables color highlighting. Color codes are emitted only on standard output; not in pipes or redirection.
Use an alias to permanently enable this option:
alias ls='ls --color=auto'
The LS_COLORS variable is used to define colors, and it configures various parts of highlighting. Use the dircolors(1) command to set it.
An advanced alternative to dircolors that ships with many themes is the vivid package, see vivid --help for usage.
--color option may incur a noticeable performance penalty when ls is run in a directory with very many entries. The default settings require ls to stat(1) every single file it lists. However, if you would like most of the file-type coloring but can live without the other coloring options (e.g. executable, orphan, sticky, other-writable, capability), use dircolors to set the LS_COLORS environment variable like this:
eval $(dircolors -p | perl -pe 's/^((CAP|S[ET]|O[TR]|M|E)\w+).*/$1 00/' | dircolors -)
See ls(1) for more information.
man
There is a real color facility in grotty(1), but it is strongly discouraged for man pages. Here we fake a colored man by hacking two main pagers, less and most: we replace the sequences for bold, standout, and underline with spiced ones that contain color.
Using bat
bat can be used as a colorizing pager for man, by setting the MANPAGER environment variable
as documented here.
Using less
See #less for a more detailed description.
export MANPAGER="less -R --use-color -Dd+r -Du+b" export MANROFFOPT="-P -c"
For Fish you could accomplish this with:
~/.config/fish/config.fish
set -xU MANPAGER 'less -R --use-color -Dd+r -Du+b' set -xU MANROFFOPT '-P -c'
Remember to source your config or restart your shell to make the changes take effect.
Using most
The basic function of 'most' is similar to less and more, but it has a smaller feature set. Configuring most to use colors is easier than using less, but additional configuration is necessary to make most behave like less.
Install the most package.
Edit /etc/man_db.conf, uncomment the pager definition and change it to:
DEFINE pager most -s
Test the new setup by typing:
$ man whatever_man_page
Modifying the color values requires editing ~/.mostrc (creating the file if it is not present) or editing /etc/most.conf for system-wide changes. Example ~/.mostrc:
% Color settings color normal lightgray black color status yellow blue color underline yellow black color overstrike brightblue black
Using X resources
A quick way to add color to manual pages viewed on xterm/uxterm or rxvt-unicode is to modify ~/.Xresources.
xterm
*VT100.colorBDMode: true *VT100.colorBD: red *VT100.colorULMode: true *VT100.colorUL: cyan
which replaces the decorations with the colors. Also add:
*VT100.veryBoldColors: 6
if you want colors and decorations (bold or underline) at the same time. See xterm(1) § veryBoldColors for more information.
rxvt-unicode
URxvt.colorIT: #87af5f URxvt.colorBD: #d7d7d7 URxvt.colorUL: #87afd7
Run:
$ xrdb -load ~/.Xresources
Launch a new xterm/uxterm or rxvt-unicode and you should see colorful man pages.
This combination puts colors to bold and underlined words in xterm/uxterm or to bold, underlined, and italicized text in rxvt-unicode. You can play with different combinations of these attributes. See the sources (archived) of this item.
pacman
Pacman has a color option. Uncomment the Color line in /etc/pacman.conf.
Wrappers
Universal wrappers
(most of them outdated, but still functioning)
They go with multiple preconfigured presets that can be changed, and new ones can be created/contributed.
-
rainbow — Colorize commands output or STDIN using patterns.
Presets: df, diff, env, host, ifconfig, java-stack-trace, jboss, jonas, md5sum, mvn2, mvn3, ping, tomcat, top, traceroute.
-
grc — Yet another colouriser for beautifying your logfiles or output of commands.
Presets: cat, cvs, df, diff, dig, gcc, g++, ls, ifconfig, make, mount, mtr, netstat, ping, ps, tail, traceroute, wdiff, blkid, du, dnf, docker, docker-machine, env, id, ip, iostat, last, lsattr, lsblk, lspci, lsmod, lsof, getfacl, getsebool, ulimit, uptime, nmap, fdisk, findmnt, free, semanage, sar, ss, sysctl, systemctl, stat, showmount, tune2fs and tcpdump.
-
cope — A colourful wrapper for terminal programs.
Presets: acpi, arp, cc, df, dprofpp, fdisk, free, g++, gcc, id, ifconfig, ls, lspci, lsusb, make, md5sum, mpc, netstat, nm, nmap, nocope, ping, pmap, ps, readelf, route, screen, sha1sum, sha224sum, sha256sum, sha384sum, sha512sum, shasum, socklist, stat, strace, tcpdump, tracepath, traceroute, w, wget, who, xrandr.
-
cw — A non-intrusive real-time ANSI color wrapper for common unix-based commands. Wraps file which can cause issues.
Presets: arp, arping, auth.log@, blockdev, cal, cksum, clock, configure, cpuinfo@, crontab@, cw-pipe, cw-test.cgi, date, df, diff, dig, dmesg, du, env, figlet, file, find, finger, free, fstab@, fuser, g++, gcc, group@, groups, hdparm, hexdump, host, hosts@, id, ifconfig, inittab@, iptables, last, lastlog, lsattr, lsmod, lsof, ltrace-color, make, md5sum, meminfo@, messages@, mount, mpg123, netstat, nfsstat, nmap, nslookup, objdump, passwd@, ping, pmap, pmap_dump, praliases, profile@, protocols@, ps, pstree, quota, quotastats, resolv.conf@, route, routel, sdiff, services@, showmount, smbstatus, stat, strace-color, sysctl, syslog, tar, tcpdump, tracepath, traceroute, umount, uname, uptime, users, vmstat, w, wc, whereis, who, xferlog.
- ccze — A fast log colorizer written in C, intended to be a drop-in replacement for colorize
Libraries for colorizing an output
- libtextstyle — A C library for styling text output to terminals
- ruby-rainbow — Rainbow is extension to ruby's String class adding support for colorizing text on ANSI terminal
- python-blessings — A thin, practical wrapper around terminal coloring, styling, and positioning
- lolcat — Ruby program that makes the output colorful like a rainbow
Application specific
Compilers
- colorgcc — A Perl wrapper to colorize the output of compilers with warning/error messages matching the gcc output format
- https://schlueters.de/colorgcc.html[dead link 2024-03-03 ⓘ] || colorgcc
diff
Diff has built-in color output, which is reasonable to use. But the following wrappers can be used:
- colordiff — Perl script for diff highlighting.
- cwdiff — (w)diff wrapper with directories support and highlighting.
- git-delta — A syntax-highlighting pager for git and diff output.
cat
- bat — Cat clone with syntax highlighting and git integration.
less
source-highlight
You can enable code syntax coloring in less. First, install source-highlight, then add these lines to your shell configuration file:
~/.bashrc
export LESSOPEN="| /usr/bin/source-highlight-esc.sh %s" export LESS='-R '
lesspipe
Frequent users of the command line interface might want to install lesspipe.
Users may now list the compressed files inside of an archive using their pager:
$ less compressed_file.tar.gz
==> use tar_file:contained_file to view a file in the archive -rw------- username/group 695 2008-01-04 19:24 compressed_file/content1 -rw------- username/group 43 2007-11-07 11:17 compressed_file/content2 compressed_file.tar.gz (END)
lesspipe also grants less the ability of interfacing with files other than archives, serving as an alternative for the specific command associated for that file-type (such as viewing HTML via python-html2text).
Re-login after installing lesspipe in order to activate it, or source /etc/profile.d/lesspipe.sh.
Make
- colormake — A simple wrapper around make to make its output more readable.
Ping
- prettyping — Add some great features to ping monitoring. A wrapper around the standard ping tool with the objective of making the output prettier, more colorful, more compact, and easier to read.
Shells
bash
See Bash/Prompt customization#Colors.
Fish
See Fish#Web interface.
xonsh
zsh
See Zsh#Colors.
Terminal emulators
Virtual console
The colors in the Linux virtual console running on the framebuffer can be changed. This is done by writing the escape code \\e]PXRRGGBB, where X is the hexadecimal index of the color from 0-F, and RRGGBB is a traditional hexadecimal RGB code.
For example, to reuse existing colors defined in ~/.Xresources, add the following to the shell initialization file (such as ~/.bashrc):
if [ "$TERM" = "linux" ]; then
_SEDCMD='s/.*\*color\([0-9]\{1,\}\).*#\([0-9a-fA-F]\{6\}\).*/\1 \2/p'
for i in $(sed -n "$_SEDCMD" $HOME/.Xresources | awk '$1 < 16 {printf "\\e]P%X%s", $1, $2}'); do
echo -en "$i"
done
clear
fi
Login screen
The below is a colored example of the virtual console login screen in /etc/issue. Create a backup of the original file with mv /etc/issue /etc/issue.bak as root, and create a new /etc/issue:
\e[H\e[2J
\e[1;30m| \e[34m\r \s
\e[36;1m/\\\\ \e[37m|| \e[36m| = \e[30m|
\e[36m/ \\\\ \e[37m|| \e[36m| \e[30m| \e[32m\t
\e[1;36m/ \e[0;36m.. \e[1m\\\\ \e[37m//==\\\\\\ ||/= /==\\\\ ||/=\\\\ \e[36m| | |/\\\\ | | \\\\ / \e[30m| \e[32m\d
\e[0;36m/ . . \\\\ \e[37m|| || || || || || \e[36m| | | | | | X \e[1;30m|
\e[0;36m/ . . \\\\ \e[37m\\\\\\==/| || \\\\==/ || || \e[36m| | | |\ \\/| / \\\\ \e[1;30m| \e[31m\U
\e[0;36m/ .. .. \\\\ \e[0;37mA simple, lightweight linux distribution. \e[1;30m|
\e[0;36m/_' `_\\\\ \e[1;30m| \e[35m\l \e[0mon \e[1;33m\n
\e[0m
See also:
- https://bbs.archlinux.org/viewtopic.php?pid=386429#p386429
- https://www.linuxfromscratch.org/blfs/view/svn/postlfs/logon.html
X window system
Most Xorg terminals, including xterm and urxvt, support at least 16 basic colors. The colors 0-7 are the 'normal' colors. Colors 8-15 are their 'bright' counterparts, used for highlighting. These colors can be modified through X resources, or through specific terminal settings. For example:
~/.Xresources
! Black + DarkGrey *color0: #000000 *color8: #555753 ! DarkRed + Red *color1: #ff6565 *color9: #ff8d8d ! DarkGreen + Green *color2: #93d44f *color10: #c8e7a8 ! DarkYellow + Yellow *color3: #eab93d *color11: #ffc123 ! DarkBlue + Blue *color4: #204a87 *color12: #3465a4 ! DarkMagenta + Magenta *color5: #ce5c00 *color13: #f57900 !DarkCyan + Cyan (both not tango) *color6: #89b6e2 *color14: #46a4ff ! LightGrey + White *color7: #cccccc *color15: #ffffff
foreground and background can be read by other applications (such as emacs). This can be avoided by specifiying the class name, for example XTerm.foreground.See also:
- #Using X resources for how to color bold and underlined text automatically.
- Color Themes - Extensive list of terminal color themes by Phraktured.
-
Xcolors by dkeg (see files with paths matching
theme/dkeg - themein the repository) - base16 color schemes
Display the 256 colors
Prints the 256 colors across the screen.
$ (x=`tput op` y=`printf %76s`;for i in {0..256};do o=00$i;echo -e ${o:${#o}-3:3} `tput setaf $i;tput setab $i`${y// /=}$x;done)
Display tput escape codes
Replace tput op with whatever tput you want to trace. op is the default foreground and background color.
$ ( strace -s5000 -e write tput op 2>&2 2>&1 ) | tee -a /dev/stderr | grep -o '"[^"]*"'
033[\033[1;34m"\33[39;49m"\033[00m
Enumerate supported colors
The following command will let you discover all the terminals you have terminfo support for, and the number of colors each terminal supports. The possible values are: 8, 15, 16, 52, 64, 88 and 256.
$ for T in `find /usr/share/terminfo -type f -printf '%f '`;do echo "$T `tput -T $T colors`";done|sort -nk2
Eterm-88color 88 rxvt-88color 88 xterm+88color 88 xterm-88color 88 Eterm-256color 256 gnome-256color 256 konsole-256color 256 putty-256color 256 rxvt-256color 256 screen-256color 256 screen-256color-bce 256 screen-256color-bce-s 256 screen-256color-s 256 xterm+256color 256 xterm-256color 256
Enumerate terminal capabilities
This command is useful to see what features that are supported by your terminal.
$ infocmp -1 | tr -d '\0\t,' | cut -f1 -d'=' | grep -v "$TERM" | sort | column -c80
acsc ed kcuu1 kich1 rmso am el kDC kLFT rmul bce el1 kdch1 km rs1 bel enacs kel kmous rs2 blink eo kend knp s0ds bold flash kEND kNXT s1ds btns#5 fsl kent kpp s2ds bw home kf1 kPRV s3ds ccc hpa kf10 kRIT sc civis hs kf11 kslt setab clear ht kf12 lines#24 setaf cnorm hts kf13 lm#0 setb colors#0x100 ich kf14 mc0 setf cols#80 ich1 kf15 mc4 sgr cr il kf16 mc5 sgr0 csr il1 kf17 mc5i sitm cub ind kf18 mir smacs cub1 indn kf19 msgr smam cud initc kf2 ncv#0 smcup cud1 is1 kf20 npc smir cuf is2 kf3 op smkx cuf1 it#8 kf4 pairs#0x7fff smso cup ka1 kf5 rc smul cuu ka3 kf6 rev tbc cuu1 kb2 kf7 ri tsl cvvis kbs kf8 rin u6 dch kc1 kf9 ritm u7 dch1 kc3 kfnd rmacs u8 dl kcbt kFND rmam u9 dl1 kcub1 kHOM rmcup vpa dsl kcud1 khome rmir xenl ech kcuf1 kIC rmkx xon
Color scheme scripts
See [3] for scripts which display a chart of your current terminal scheme.
True color support
Some terminals support the full range of 16 million colors (RGB, each with 8 bit resolution): xterm, konsole, st, etc. The corresponding TERM values xterm-direct, konsole-direct, st-direct, etc. are supported starting with ncurses version 6.1 [4]. For more info about terminal emulators and applications that support true color, see [5].
Note that the Linux kernel supports the SGR (Select Graphic Rendition) escape sequences for true-color, but it is pointless to use it, because the driver maps the 24-bit color specifications to a 256-colors color map in the kernel (see the functions rgb_foreground, rgb_background). For this reason, there is no terminfo entry linux-direct.