Re: Bug#582083: patch for grep --color to non-tty output

[Tim Connors]

On Tue, 24 Apr 2012, Jim Meyering wrote:

> Aníbal Monsalve Salazar wrote:
> > Debian bug report is posted at:
> >
> > http://bugs.debian.org/582083
> ...
> >>There's no reason not to obey the user when they ask for "--color",
> >>regardless of whether the output is to a tty or not.  They wouldn't
> >>have asked for --color if they didn't want it, and most other gnu
> >>programs assume --color=yes rather than --color=auto when supplied with
> >>just --color.  Man and info pages and translations appear to need to
> >>work since they don't imply what the default is.  Nice easy patch to
> >>apply!
> >>
> >>[1] New version looks like:
> >>diff -ru grep-2.10//src/main.c /tmp/grep-2.10//src/main.c
> >>--- grep-2.10//src/main.c       2012-04-24 13:11:57.000000000 +1000
> >>+++ /tmp/grep-2.10//src/main.c  2012-04-24 12:56:47.000000000 +1000
> >>@@ -2059,7 +2059,7 @@
> >>           else
> >>             show_help = 1;
> >>         } else
> >>-          color_option = 2;
> >>+          color_option = 1;
> >>         if (color_option == 2)
> >>           {
> >>             char const *t;
>
> Thanks for the report of the documentation bug and the patch, but the patch
> (changing the meaning of --color from --color=auto to --color=always)
> would break existing usage.
>
> Currently, people can use --color in an always-on alias/function
> or set the GREP_OPTIONS=--color envvar and get colorized output,
> yet not have those ANSI terminal highlighting bytes interfere
> with output that is not to a tty.
>
> If we were to make your proposed change, they'd find those
> color codes in unexpected (and undesirable) places.

Easy to fix!  Fix the bug in their login scripts!

> However, this is definitely a documentation bug, and I'd
> appreciate a patch for both --help and grep.texi.
>
> Jim
>
> PS.  True, it is undesirable to have grep's --color(with no value)
> default to "auto", when in ls it defaults to "always", but changing
> grep's default now would be too disruptive.  We'd have to warn that
> the default is going to change for a year or two before making the
> actual change, and even then, some users would be impacted.

It doesn't take much to change one's .rc files to say
GREP_OPTIONS="--color=auto" rather than "--color"!  They should have been
doing that all along (because they were relying on undocumented behaviour
:).

I personally have "GREP_OPTIONS=--color=auto".  If the output is a tty,
that works as expected.  If the output is a pipe, no color as expected;
all good.  If the output is "less -R", I want --color, so I say
"echo test | grep --color es", and I don't get color.  That's not what I
asked for!



-- 
Tim Connors