When I read a file in Linux with the command less
or more
, how can I get the content in colors?
(update on 2020)
The faster way would be using less -R
ref. https://superuser.com/a/117842/34893
You can utilize the power of pygmentize with less - automatically! (No need to pipe by hand.)
Install pygments
with your package manager or pip (possibly called python-pygments
) or get it here http://pygments.org/download/.
Write a file ~/.lessfilter
#!/bin/sh
case "$1" in
*.awk|*.groff|*.java|*.js|*.m4|*.php|*.pl|*.pm|*.pod|*.sh|\
*.ad[asb]|*.asm|*.inc|*.[ch]|*.[ch]pp|*.[ch]xx|*.cc|*.hh|\
*.lsp|*.l|*.pas|*.p|*.xml|*.xps|*.xsl|*.axp|*.ppd|*.pov|\
*.diff|*.patch|*.py|*.rb|*.sql|*.ebuild|*.eclass)
pygmentize -f 256 "$1";;
.bashrc|.bash_aliases|.bash_environment)
pygmentize -f 256 -l sh "$1";;
*)
if grep -q "#\!/bin/bash" "$1" 2> /dev/null; then
pygmentize -f 256 -l sh "$1"
else
exit 1
fi
esac
exit 0
In your .bashrc
add
export LESS='-R'
export LESSOPEN='|~/.lessfilter %s'
Also, you need to make ~/.lessfilter
executable by running
chmod u+x ~/.lessfilter
Tested on Debian.
You get the idea. This can of course be improved further, accepting more extensions or parsing the shebang for other interpreters than bash. See some of the other answers for that.
The idea came from an old blog post from the makers of Pygments, but the original post doesn't exist anymore.
-
6If you want to have coloring of the source code files, you also need to make ~/.lessfilter executable by running
chmod u+x ~/.lessfilter
. You also need to have pygmentize (pygments.org/download) installed. – Sergiy Belozorov Dec 18 '12 at 11:07 -
7@puk you can do something like
ls --color=always -l | less -R
. Obviously a lot to type but you could alias it to something likell
. That is if you don't want to use any extra libraries. – PhilT Jul 23 '14 at 16:17 -
2
-
2My edit was rejected so I guess I'll post it as a comment instead: Don't test the exit codes of commands indirectly. You can use
if grep -q "#\!/bin/bash" "$1"
(the-q
suppresses standard output). You may want to redirect standard error with2>/dev/null
. – Tom Fenech Oct 23 '15 at 13:16 -
3To get a list of all unique file extensions supported by your currently installed pygmentize version, in a format suitable for pasting into this .lessfilter script, run
pygmentize -L | grep -o "(filenames .*)" | sed -E "s,\(filenames (.*)\),\1,gm;s/, /\n/g" | sort -u | tr "\n" "|"
. Note that on certain Linuxes, settingLESSOPEN
may not be necessary because it is already setup to uselesspipe
which detects the .lessfilter file already (runecho $LESSOPEN
to check). – Bart May 17 '19 at 9:38
Try the following:
less -R
from man less
:
-r
or--raw-control-chars
Causes "raw" control characters to be displayed. (...)
-R
or--RAW-CONTROL-CHARS
Like
-r
, but only ANSI "color" escape sequences are output in "raw" form. (...)
-
19This is useful when the file itself contains the escape codes that will need to be displayed. – Nitrodist Dec 16 '11 at 21:16
-
58It should be noted that most programs use the
isatty(2)
syscall to check whether their standard output is a terminal, and usually disable colorized output if it is not. For any pipe to less,isatty
will return 0. To check whether this works, tryecho -e '\x1b[32;1mtest\x1b[m' | less -r
– mic_e Sep 24 '13 at 22:53 -
11
-
19
-
6This worked for me with grep only when I included the
--color=always
option in grep.:grep --color=always foo myfile.txt | less -R
– Dannid Jan 14 '19 at 17:31
I got the answer in another post: Less and Grep: Getting colored results when using a pipe from grep to less
When you simply run
grep --color
it impliesgrep --color=auto
which detects whether the output is a terminal and if so enables colors. However, when it detects a pipe it disables coloring. The following command:grep --color=always "search string" * | less -R
Will always enable coloring and override the automatic detection, and you will get the color highlighting in less.
Warning: Don't put --color=always
as an alias, it break things sometimes. That's why there is an --color=auto
option.
-
6Nice, thanks. Except that I need to use
-R
as an option toless
, as well. – naught101 May 8 '12 at 6:41 -
10I believe
grep -R
is for specifying recursive search.less -R
is necessary forless
to correctly spit the colors back out.grep --color=always [grep cmds] | less -R
works for me on OS X 10.7.3! – Steven Lu May 9 '12 at 13:56 -
2Is there anyway to let grep know just pipe less -R command and then just do coloring? So, we don't have to put --color=always and less -R all the time. – A-letubby Feb 27 '15 at 7:50
-
1
-
1This also works when you need to pipe
git diff
toless
. Doing just this:git diff | less
won't show you any colors. You need to do this instead:git diff --colors=always | less
orgit diff --colors=always some_file | less
. (I'm using cygwin on Windows 10, by the way.) – CSCH Aug 27 '18 at 20:17
Use view
instead of less
. It opens the file with vim
in readonly mode.
It's practically a coloured less
: a pager where you can search with / (and more). The only drawback is that you can't exit with q but you need :q
Also, you get the same colouring as vim
(since you're in fact using vim
).
-
How about the performance of big files? Vim syntax highlighting is know to be slow on huge files. – pihentagy Feb 20 '14 at 10:28
-
1I upvoted (I didn't know about
view
) but another downside is that j/k/up/down don't instantly scroll, since there is a cursor. – Tyler Collier Mar 1 '15 at 17:38 -
9
-
8
vim
is an editor, which loads the complete file into memory, whereasless
is a pager, loading the file only partially into memory. You will know the difference with huge files. – sjas Jul 20 '16 at 12:13 -
1@RiccardoGalli - Cool idea, but i would agree about the performance concern, it's not instantaneous. When viewing huge logs or greps, especially over-the-line (SSH),
less
is faster since it's not dumping the entire output line by line via "inserts" intovim
. Also, you can search withless
using '/'. Additionally it has a "tail" mode using shift-F which is handy. – dhaupin Sep 29 '16 at 17:49
To tell less to show colors call it with -R:
less -R
Unfortunately some programs detect that their stdout is not a terminal and disable colors - e.g pacman (Arch Linux package manager).
In those cases its possible to use unbuffer
:
unbuffer <command> | less -R
Example using pacman
unbuffer pacman -Ss firefox | less -R
The unbuffer
command is usually part of the package expect
(Arch Linux, Debian/Ubuntu) or expect-dev
(legacy versions of Debian/Ubuntu).
To answer the question for completeness:
As others already answered, pygmentize
is great for colorizing source code. It does not require unbuffer
. Easiest call:
pygmentize someSource.cpp | less -R
-
2
-
1
-
I was trying to pipe dmesg output to check on boot errors but the colours didn't work unless I use unbuffer, which was confusing the heck out of me:
unbuffer dmesg | less -R
works as expected. – pbhj May 12 '19 at 9:49 -
1on macOS
brew install expect
gets you the necessaryunbuffer
command. – luckman212 Oct 19 '19 at 20:30
pygmentize
supports the -g
option to automatically guess the lexer to be used which is useful for files read from STDIN
without checking any extension type.
Using that, you only need to set the following 2 exports in your .bashrc
without any additional scripts:
export LESS='-R'
export LESSOPEN='|pygmentize -g %s'
-
4Concise and effective. I prefer defining an alias, because sometimes less is better. So: alias lesc='LESS="-R" LESSOPEN="|pygmentize -g %s" less' – Tiago Apr 28 '14 at 18:27
You didn't say what this color should mean, e.g. what should the colors be for a text file?
If what you want is syntax highlighting for source code, you need a source code highlighter. I sometimes use pygmentize like this
pygmentize file.cpp | less
or
pygmentize file.cpp | more
There are other highlighters around.
This is pretty fast. If you don't mind firing up vim
there is a read-only mode that can give you syntax highlighting if you have it in vim
.
view file.cpp
or alternatively see churnd's answer.
This is yet another pygments-based answer, with several major improvements:
- does not break
lesspipe
orlessfile
filters - works with multiple inputs to
less
- correctly parses the script type from the shebang header
- works for all 434 file types lexable by Pygments
- color scheme is parameterized as an environment variable
EDIT: I maintain an updated/improved version of this script here: https://github.com/CoeJoder/lessfilter-pygmentize
Original version below:
Install Pygments and Gawk
sudo apt-get install python-pygments python3-pygments gawk
Set Environment Variables
Check whether lesspipe
or lessfile
is already enabled:
echo $LESSOPEN
If you don't see either program referenced there, ensure that lesspipe
is installed (most distros come with it).
Add the following to ~/.bashrc
:
# sets LESSOPEN and LESSCLOSE variables
eval "$(SHELL=/bin/sh lesspipe)"
# interpret color characters
export LESS='-R'
# to list available styles: `pygmentize -L styles`
export PYGMENTIZE_STYLE='paraiso-dark'
# optional
alias ls='ls --color=always'
alias grep='grep --color=always'
If you don't want lesspipe
, replace the eval
statement with:
export LESSOPEN='|~/.lessfilter %s'
Create ~/.lessfilter
Add the following code and make the file executable: chmod u+x ~/.lessfilter
#!/bin/bash
for path in "$@"; do
# match by known filenames
filename=$(basename "$path")
case "$filename" in
.bashrc|bash.bashrc|.bash_aliases|.bash_environment|.bash_profile|\
.bash_login|.bash_logout|.profile|.zshrc|.zprofile|.zshrc|.zlogin|\
.zlogout|zshrc|zprofile|zshrc|zlogin|zlogout|.cshrc|.cshdirs|\
csh.cshrc|csh.login|csh.logout|.tcshrc|.kshrc|ksh.kshrc)
# shell lexer
pygmentize -f 256 -O style=$PYGMENTIZE_STYLE -l sh "$path"
;;
.htaccess|apache.conf|apache2.conf|Dockerfile|Kconfig|external.in*|\
standard-modules.in|nginx.conf|pacman.conf|squid.conf|termcap|\
termcap.src|terminfo|terminfo.src|control|sources.list|CMakeLists.txt|\
Makefile|makefile|Makefile.*|GNUmakefile|SConstruct|SConscript|\
.Rhistory|.Rprofile|.Renviron|Rakefile|Gemfile|PKGBUILD|autohandler|\
dhandler|autodelegate|.vimrc|.exrc|.gvimrc|vimrc|exrc|gvimrc|todo.txt)
# filename recognized
pygmentize -f 256 -O style=$PYGMENTIZE_STYLE "$path"
;;
*)
ext=$([[ "$filename" = *.* ]] && echo ".${filename##*.}" || echo '')
case "$ext" in
.as|.mxml|.bc|.g|.gd|.gi|.gap|.nb|.cdf|.nbp|.ma|.mu|.at|.run|\
.apl|.adl|.adls|.adlf|.adlx|.cadl|.odin|.c-objdump|.s|\
.cpp-objdump|.c++-objdump|.cxx-objdump|.d-objdump|.S|.hsail|\
.ll|.asm|.ASM|.objdump-intel|.objdump|.tasm|.au3|.ahk|.ahkl|\
.bb|.decls|.bmx|.bas|.monkey|.BAS|.bst|.bib|.abap|.ABAP|.cbl|\
.CBL|.cob|.COB|.cpy|.CPY|.gdc|.maql|.p|.cls|.c|.h|.idc|.cpp|\
.hpp|.c++|.h++|.cc|.hh|.cxx|.hxx|.C|.H|.cp|.CPP|.ino|.clay|\
.cu|.cuh|.ec|.eh|.mq4|.mq5|.mqh|.nc|.pike|.pmod|.swg|.i|.vala|\
.vapi|.capnp|.chpl|.icl|.dcl|.cf|.docker|.ini|.cfg|.inf|\
.pc|.properties|.reg|.tf|.pypylog|.cr|.csd|.orc|.sco|.css|\
.less|.sass|.scss|.croc|.d|.di|.smali|.jsonld|.json|.yaml|\
.yml|.dpatch|.darcspatch|.diff|.patch|.wdiff|.boo|.aspx|.asax|\
.ascx|.ashx|.asmx|.axd|.cs|.fs|.fsi|.n|.vb|.als|.bro|.crmsh|\
.pcmk|.msc|.pan|.proto|.pp|.rsl|.sbl|.thrift|.rpf|\
.dylan-console|.dylan|.dyl|.intr|.lid|.hdp|.ecl|.e|.elm|.ex|\
.exs|.erl|.hrl|.es|.escript|.erl-sh|.aheui|.befunge|.bf|.b|\
.camkes|.idl4|.cdl|.cw|.factor|.fan|.flx|.flxh|.frt|.f|.F|\
.f03|.f90|.F03|.F90|.PRG|.prg|.go|.abnf|.bnf|.jsgf|.cyp|\
.cypher|.asy|.vert|.frag|.geo|.plot|.plt|.ps|.eps|.pov|.inc|\
.agda|.cry|.hs|.idr|.kk|.kki|.lagda|.lcry|.lhs|.lidr|.hx|\
.hxsl|.hxml|.sv|.svh|.v|.vhdl|.vhd|.dtd|.haml|.html|.htm|\
.xhtml|.xslt|.pug|.jade|.scaml|.xml|.xsl|.rss|.xsd|.wsdl|\
.wsf|.xpl|.pro|.ipf|.nsi|.nsh|.spec|.i6t|.ni|.i7x|.t|.io|\
.ijs|.coffee|.dart|.eg|.js|.jsm|.juttle|.kal|.lasso|\
.lasso[89]|.ls|.mask|.j|.ts|.tsx|.jl|.aj|.ceylon|.clj|\
.cljs|.golo|.gs|.gsx|.gsp|.vark|.gst|.groovy|.gradle|.ik|\
.java|.kt|.pig|.scala|.xtend|.cpsa|.cl|.lisp|.el|.hy|.lsp|.nl|\
.kif|.rkt|.rktd|.rktl|.scm|.ss|.shen|.xtm|.cmake|.mak|.mk|\
.[1234567]|.man|.md|.css.in|.js.in|.xul.in|.rst|.rest|.tex|\
.aux|.toc|.m|.sci|.sce|.tst|.ml|.mli|.mll|.mly|.opa|.sml|.sig|\
.fun|.bug|.jag|.mo|.stan|.def|.mod|.mt|.ncl|.nim|.nimrod|.nit|\
.nix|.cps|.x|.xi|.xm|.xmi|.mm|.swift|.ooc|.psi|.psl|.G|.ebnf|\
.rl|.treetop|.tt|.adb|.ads|.ada|.pas|.dpr|.pwn|.sp|.pl|.pm|\
.nqp|.p6|.6pl|.p6l|.pl6|.6pm|.p6m|.pm6|.php|.php[345]|.zep|\
.praat|.proc|.psc|.lgt|.logtalk|.prolog|.pyx|.pxd|.pxi|.dg|\
.py3tb|.py|.pyw|.sc|.tac|.sage|.pytb|.qvto|.Rout|.Rd|.R|.rq|\
.sparql|.ttl|.r|.r3|.reb|.red|.reds|.txt|.rnc|.graph|\
.instances|.robot|.fy|.fancypack|.rb|.rbw|.rake|.gemspec|\
.rbx|.duby|.rs|.rs.in|.SAS|.sas|.applescript|.chai|.ezt|\
.mac|.hyb|.jcl|.lsl|.lua|.wlua|.moo|.moon|.rexx|.rex|.rx|\
.arexx|.sh|.ksh|.bash|.ebuild|.eclass|.exheres-0|.exlib|.zsh|\
.sh-session|.shell-session|.bat|.cmd|.fish|.load|.ps1|.psm1|\
.tcsh|.csh|.ns2|.st|.smv|.snobol|.rql|.sql|.sqlite3-console|\
.do|.ado|.scd|.tcl|.rvt|.ng2|.tmpl|.spt|.cfc|.cfm|.cfml|\
.evoque|.kid|.handlebars|.hbs|.phtml|.jsp|.liquid|.mao|.mhtml|\
.mc|.mi|.myt|.rhtml|.tpl|.ssp|.tea|.twig|.vm|.fhtml|.sls|\
.feature|.tap|.awk|.vim|.pot|.po|.weechatlog|.todotxt|.thy|\
.lean|.rts|.u|.vcl|.bpl|.sil|.vpr|.cirru|.duel|.jbst|.qml|\
.qbs|.slim|.xqy|.xquery|.xq|.xql|.xqm|.whiley|.x10)
# extension recognized
pygmentize -f 256 -O style=$PYGMENTIZE_STYLE "$path"
;;
*)
# parse the shebang script header if it exists
lexer=$(head -n 1 "$path" |grep "^#\!" |awk -F" " \
'match($1, /\/(\w*)$/, a) {if (a[1]!="env") {print a[1]} else {print $2}}')
case "$lexer" in
node|nodejs)
# workaround for lack of Node.js lexer alias
pygmentize -f 256 -O style=$PYGMENTIZE_STYLE \
-l js "$path"
;;
"")
exit 1
;;
*)
pygmentize -f 256 -O style=$PYGMENTIZE_STYLE \
-l $lexer "$path"
;;
esac
;;
esac
;;
esac
done
exit 0
-
-
TIL: If you get an error like "awk: line 1: syntax error at or near ," with the above .lessfilter in place, check that gawk is installed. – Bryce Oct 23 '19 at 23:38
Use the GNU Source-highlight; you can install it with apt
if you have it, or otherwise install it from source. Then set up an "input preprocessor" for less, with help from the Source-highligh' documentations for setting up with less:
This was suggested by Konstantine Serebriany. The script src-hilite-lesspipe.sh will be installed together with source-highlight. You can use the following environment variables:
export LESSOPEN="| /path/to/src-hilite-lesspipe.sh %s"
export LESS=' -R '
This way, when you use less to browse a file, if it is a source file handled by source-highlight, it will be automatically highlighted.
Xavier-Emmanuel Vincent recently provided an alternative version of ANSI color scheme, esc256.style: some terminals can handle 256 colors. Xavier also provided a script which checks how many colors your terminal can handle, and in case, uses the 256 variant. The script is called source-highlight-esc.sh and it will be installed together with the other binaries.
To expand upon another answer, you can make it work for most if not all of your scripts that don't have extensions by changing the .lessfilter file around just a bit:
#!/bin/sh
case "$1" in
*.awk|*.groff|*.java|*.js|*.m4|*.php|*.pl|*.pm|*.pod|*.sh|\
*.ad[asb]|*.asm|*.inc|*.[ch]|*.[ch]pp|*.[ch]xx|*.cc|*.hh|\
*.lsp|*.l|*.pas|*.p|*.xml|*.xps|*.xsl|*.axp|*.ppd|*.pov|\
*.diff|*.patch|*.py|*.rb|*.sql|*.ebuild|*.eclass)
pygmentize -f 256 "$1";;
.bashrc|.bash_aliases|.bash_environment)
pygmentize -f 256 -l sh "$1"
;;
*)
scriptExec=$(head -1 "$1" |grep "^#\!" |awk -F" " '{print $1}')
scriptExecStatus=$?
if [ "$scriptExecStatus" -eq "0" ]; then
lexer=$(echo $scriptExec |awk -F/ '{print $NF}')
pygmentize -f 256 -l $lexer "$1"
else
exit 1
fi
esac
exit 0
You'd still need to add the two variables to .bashrc:
export LESS='-R'
export LESSOPEN='|~/.lessfilter %s'
And you'll still need to make .lessfilter executable:
$ chmod 700 ~/.lessfilter
Also I wanted to add that under debian the pygments package is called python-pygments. I had trouble locating it at first because the obvious misspelling of "pigments" as "pygments" wasn't enough of a hint to me that it was a package that might be prefixed with "python-" by the package manager.
-
22 comments: 1) Thanks for the improvement. 2) Phrases like "voted best answer" aren't great; that may change (in fact, if this is better than that answer, this post might become the top answer, at which point it'll just be confusing. Maybe just say "to expand upon another answer" or "captaincomic's answer"? – cpast Feb 27 '13 at 23:07
Condensed from my full blog post about improving less experience: https://www.topbug.net/blog/2016/09/27/make-gnu-less-more-powerful/
For colorful manpages, add the following to your .bashrc
or .zshrc
:
export LESS_TERMCAP_mb=$'\E[1;31m' # begin bold
export LESS_TERMCAP_md=$'\E[1;36m' # begin blink
export LESS_TERMCAP_me=$'\E[0m' # reset bold/blink
export LESS_TERMCAP_so=$'\E[01;44;33m' # begin reverse video
export LESS_TERMCAP_se=$'\E[0m' # reset reverse video
export LESS_TERMCAP_us=$'\E[1;32m' # begin underline
export LESS_TERMCAP_ue=$'\E[0m' # reset underline
For syntax highlighting, using an existing powerful lesspipe.sh
to handle it instead of writing your own: https://github.com/wofr06/lesspipe
You can consider using most
utility which is colour-friendly alternative for less
and more
.
-
can you show us one example? I tried here, and the output was black and white. – danilo Jun 13 '19 at 17:47
-
Your input should contain colours. First produce a colorised sample (e.g.
ccze -A </var/log/dpkg.log
,ls -1 --color /var/log
) then pipe it tomost
:ls -1 --color /var/log | most
. – Onlyjob Jun 15 '19 at 0:06 -
-
-
Make sure that your command produces colours before piping to
less
or others. Make sure your terminal emulator can output colours. CheckTERM
environment variable. Read more in unix.stackexchange.com/questions/148/… When possible use modern GNU+Linux distribution like Debian. Use search engine (e.g. duckduckgo.com startpage.com) to find answers. Remember that comments are not for discussion. – Onlyjob Jun 16 '19 at 5:06
I found this simple elegant solution. You don't have to install anything extra as it is already there by default on most machines. As vim
is installed by default on most machines, it includes a macro to run vim
like less
Some of the options to use it are to create an alias:
alias vless='vim -u /usr/share/vim/vim74/macros/less.vim'
or create a symbolic link:
ln -s /usr/share/vim/vim74/macros/less.sh ~/bin/vless
Then you just run vless myfile.py
I got most of the information here
-
1I have
alias lesser='/usr/share/vim/vim80/macros/less.sh'
in~/bash_aliases
(in Ubuntu 18.04). Can use shortcuts such as f forward, b backward, d half down, u half up, q quit, etc... – Daniel Jun 5 '19 at 14:01
The most intuitive and straight forward solution for me was using pygmentize
by adding the lines below to .bashrc
export LESS='-R'
export LESSOPEN='|pygmentize -g %s'
In case you couldn't call pygmentize
, just install like
pip install pygments
ps. The pygmentize
executable binary would sit in /usr/local/bin/
or in your /home/username/.virtualenv/venvname/bin/
or somewhere.
An alternative to less/more that works with colors out of the box is bat. You can install it with most package managers use it as a pager as well as a cat replacement.
None of these were working out of the box for me and I figured out an easy way to make this work so I thought I would share.
Just use tmux, that allows you access and scroll through a larger history and preserves the colors perfectly.
-
1Doesn't tmux permit multiple terminals from one screen, how does it change less's display of colours? – Xen2050 Oct 26 '18 at 13:23
-
@Xen2050 I think it's a neat workaround although this answer doesn't explain how to enter scroll mode (Ctrl-b + [) – siikamiika Apr 18 '19 at 18:30
As long as the output text have color control characters, less -R
will do.
-
This is what another answer (from 9 years ago) says. Answers that duplicate other answers are not useful. – Kamil Maciorowski Jul 15 '19 at 12:54
-
Fair, but that answer doesn't make it explicit that it only works on files that were built with color control characters. – Leonardo Raele Jul 15 '19 at 13:13
less
: colors are lost. (The answers to that ”piping issue“ involveless -R
,unbuffer
etc.) But the actual question refers to opening a file! — The ambiguity lies primarily in the question's title, but even besides that, IMHO the question is still too broad: ”read a file“ could refer to any file (probably plain text). (well, ”get the content in colors“ is probably referring to syntax highlighting.) – myrdd Dec 3 '18 at 23:05less -R
will work on files as well, e.g.ls --color=always > /tmp/file && less -R /tmp/file
– Gert van den Berg Jul 5 '19 at 10:20