Arch Linux

jjt3hii

Member

Registered: 2008-06-09

Posts: 22

color with more, less, tail, head, ect?

Is it possible to have the more, less, tail, or head commands retain the color in the console?  For instance, "pacman-color -Ss kde4 | more" will strip all the colors.  ...or is there an alternative command that I may not know about that retains the colors?

Thanks,

Jason

Procyon

Member

Registered: 2008-05-07

Posts: 1,819

Re: color with more, less, tail, head, ect?

As you noticed apps can see if they output to tty or a pipe. I don't know about pacman-color (check its man page), but for ls and grep and such there is --color=always. And then less has -R to interpret it correctly (not sure if it's necessary).

plurt

Member

Registered: 2008-10-16

Posts: 88

Re: color with more, less, tail, head, ect?

I'm not sure if it's exactly what you need, but it might be helpfull, check this post:
http://bbs.archlinux.org/viewtopic.php? … 69#p518569

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quarkup

Member

From: Portugal

Registered: 2008-09-07

Posts: 497

Website

Re: color with more, less, tail, head, ect?

My bash's colors:
-> $PS1 (the prompt)
-> ls
-> grep
-> vi
-> manpages
-> colordiff
-> pacman-color
-> colorgcc

these lines below work for the manpages,  but they do not work on less.
export LESS_TERMCAP_md=$'\e[01;34m';
export LESS_TERMCAP_mb=$'\e[00;34m';
export LESS_TERMCAP_me=$'\e[00;00m';
export LESS_TERMCAP_se=$'\e[00;00m';
export LESS_TERMCAP_so=$'\e[01;31m';
export LESS_TERMCAP_ue=$'\e[00;00m';
export LESS_TERMCAP_us=$'\e[01;32m';

Last edited by quarkup (2009-03-20 21:19:17)

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bernarcher

Forum Fellow

From: Germany

Registered: 2009-02-17

Posts: 2,281

Re: color with more, less, tail, head, ect?

Generally you can feed color codes through less -R. However this appears not to work with pacman-color.
This is what I found here (on an xterm).
pacman-color -Ss kde4 produces colored output
pacman-color -Ss kde4 | less -R produces b/w output

However:
yaourt -Ss kde4 | less -R produces colored output

I do not have the time now to view the pacman-color script. Does anyone know how it does handle colors?

Last edited by bernarcher (2009-03-21 00:26:11)

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Procyon

Member

Registered: 2008-05-07

Posts: 1,819

Re: color with more, less, tail, head, ect?

@bernarcher: Or specifically, does an app exist that can fool a program into thinking it is outputting to a tty?

e.g.
ls --color=auto gives color
ls --color=auto | less gives no color
faketty ls --color=auto | less would give color

Last edited by Procyon (2009-03-21 00:48:57)

bernarcher

Forum Fellow

From: Germany

Registered: 2009-02-17

Posts: 2,281

Re: color with more, less, tail, head, ect?

faketty ls --color=auto | less would give color

A bit off-topic, but I am completely ignorant of faketty.
It is a kernel module, right? I just can't find suitable info (did some simple google search only).

BTW: ls -l --color=auto works, ls -l --color=auto | less -R does not.
Looks like I am missing some in-depth understanding of how color control works with less. Are there any docs about this topic?

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Procyon

Member

Registered: 2008-05-07

Posts: 1,819

Re: color with more, less, tail, head, ect?

No, I was wondering if something exists that could do that, I don't know of any faketty program. Well it's not a big deal of course.

The color control is not about less, but it is ls that knows it is outputting to a pipe, and then decides to strip all colors from output.

test1000

Member

Registered: 2005-04-03

Posts: 834

Re: color with more, less, tail, head, ect?

ls --color=auto means: show colors if stdout is a terminal, if the output is(sent into) a pipe, don't use colors.

you have to use the always flag if you always want colors... same behaviour in grep and some other tools too if i recall correctly.

btw, this is in info documentation(for colored info docs, use pinfo). 'pinfo ls'

Last edited by test1000 (2009-03-21 10:57:36)

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bernarcher

Forum Fellow

From: Germany

Registered: 2009-02-17

Posts: 2,281

Re: color with more, less, tail, head, ect?

ls --color=auto means: show colors if stdout is a terminal, if the output is(sent into) a pipe, don't use colors.

you have to use the always flag if you always want colors... same behaviour in grep and some other tools too if i recall correctly.

btw, this is in info documentation(for colored info docs, use pinfo). 'pinfo ls'

--color=always This was it!
I always did alias to ls='ls --color=auto', although I should have known better, having read man ls, info ls so many times.

When feeding through less, remember to allow raw control codes, though.
ls -l --color=always | less -R
does its coloring job.

Ah, well, another topic to remember firmly. Thanks!

Last edited by bernarcher (2009-03-21 12:39:25)

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To know or not to know ...
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