I use the --colour option of grep a lot, but I often use less as well. How can I pipe grep results to less and still preserve the coloring. (Or is that possible?)

grep "search-string" -R * --colour | less 


I'm looking for a direct solution or anything equivalent to this.

  • What does * do? From the man page of grep: *: The preceding item will be matched zero or more times. But I still don't understand..! @JeremyPowell – Shayan Sep 1 '19 at 17:37
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    @Shayan, the '*' in this case is for the file arguments. It gets processed by the shell which expands it to all files in the directory. The search string is enclosed in double quotes in the example. – NeilG Nov 2 '19 at 4:15

When you simply run grep --color it implies grep --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 -R "search string" * | less

Will always enable coloring and override the automatic detection, and you will get the color highlighting in less.

EDIT: Although using just less works for me, perhaps older version require the -R flag to handle colors, as therefromhere suggested.

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    You need to use less -R for the colour encoding to be interpreted by less correctly – therefromhere Sep 4 '09 at 23:24
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    It worked for me with just less, it may be version dependent. – drrlvn Sep 5 '09 at 12:14
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    A (hopefully) useful addendum: I needed to exclude some matches but maintain the colouring, so I actually ended up with grep pattern file | grep -v badpattern | grep --colour=always pattern | less -R, which met my needs perfectly. (Thanks again!) – Owen Blacker Mar 6 '12 at 15:35
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    I can't believe they just implemented the color-handling feature in less and therefore missed the chance to have a special colorless tool. For the name alone it should have been done! I should probably write a patch that invokes -R automatically when the binary is run as colorless. – Christian Jul 10 '13 at 0:42
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    @OwenBlacker It might not be an alias. You might have $LESS set with -R. – greyfade Aug 30 '16 at 21:01

You can put this in your .bashrc file:

export GREP_OPTIONS="--color=always"

or create an alias like this:

alias grepc="grep --color=always"

and you will need to use the -R option for less, as pointed out by therefromhere

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    Warning!: GREP_OPTIONS="--color=always" may break many scripts that use grep (or (e|f)grep). – mctylr Mar 12 '10 at 19:25
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    Yeah, better to just alias grep. You can always get pure grep with GREP, or override the --color option manually. – asmeurer Jul 18 '11 at 22:51
  • This doesn't work for me, alias does work though. – saeedgnu Feb 28 '14 at 3:30

In case like this, I prefer to actually create small sh files and put them on /usr/local/bin.
I usually use grep in the recursive way on the pwd, so thats my personal script:

grep --color=always -r "$@" . | less -R

And then I've just copied it as /usr/local/bin/g (yes, I use it a lot)

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    Why not just use shell functions for this kind of thing? g() { grep --color=always -r "$@" . | less -R } works identically and probably will give (minutely) better performance. – 00dani Jan 11 '17 at 2:00
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    @00dani yeah, that's a valid alternative too and sometimes I use it. Please note that in this case, most time is spent in IO and therefore there is no perceivable performance boost :) Another difference is that once in your PATH, this script can be used with other shell scripts and aliases too; the function instead needs to be explicitly loaded – Iazel Jan 27 '19 at 12:15

Don't alias "grep", better to alias "less" which is never used by shells. In your .bashrc just put: alias less="less -r".

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    Not quite right. One needs to use both grep --color=always and less -R. Note that grep only knows it is being piped into some other process and the --color=auto option uses solely this information to decide if will output colors or not. – brandizzi Apr 17 '13 at 18:35
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    Note that less option -r is different than -R. Probably -R is safer. – Craig McQueen Jan 9 '14 at 0:26
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    So why down-vote my solution. The OP specifically ask for less with the example already using `--color' option. – not2qubit Jan 9 '14 at 15:58
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    An alias is probably undesirable here. less supports a $LESS environment variable. So, instead of an alias, export LESS='-R' might be preferable. – greyfade Aug 30 '16 at 20:59

I need to run

grep --color=always -R "search string" * | less - r

with the -r flag after less, in order this to run.

  • What does * do? From the man page of grep: *: The preceding item will be matched zero or more times. But I still don't understand..! – Shayan Sep 1 '19 at 17:36
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    @Shayan It will search for the text "search string" in all files. – Pepedou Jun 1 '20 at 19:41

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