Re: Highlighting in grep buffer

[Juri Linkov]

Richard Stallman <address@hidden> writes:
> It is quite simple, but I can't understand it at all.
> It needs comments to explain what GREP_COLOR means
> and what that value means and why.

According to grep man page, the environment variable GREP_COLOR
specifies the marker for highlighting, GREP_OPTIONS specifies default
options to be placed in front of any explicit options, and the option
--color surrounds the matching string with the marker found in GREP_COLOR
environment variable.

Actually, markers are ANSI escape sequences like ^[[01;31m and ^[[00m
before and after the matching string.

> It may be less reliable, in that it may not work with non-GNU grep
> programs.  Perhaps that is ok; people should install GNU grep.

Even though this feature will not be available for non-GNU greps,
I can't tell if the GREP_OPTIONS=--colors will cause them to fail.
If so, a new check for the --colors availability could be added to
the grep.el.

But for GNU grep this feature is the most reliable way to find
positions of matching strings.

-- 
Juri Linkov
http://www.jurta.org/emacs/