Debian Bug report logs - #475772
dpkg should set GREP_OPTIONS

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Message #5 received at submit@bugs.debian.org (full text, mbox, reply):

From: Kevin Hunter <hunteke@earlham.edu>

To: submit@bugs.debian.org

Subject: dpkg should set GREP_OPTIONS

Date: Sat, 12 Apr 2008 16:52:47 -0400

Package: a lot of them

I've recently set GREP_OPTIONS='--color=always' in my bashrc.  I do this 
mainly so that I can see grep's highlighted findings even when viewing 
through a pipeline, such as with less.  '--color=auto' won't work 
because it will turn off the color escapes if it's going down the 
pipeline, which is not what I want when I use less.

This poses a problem for a lot of scripts, which assume that text coming 
from their stdin is free from (color) escapes.  For instance, I recently 
went to install postgresql-client-8.2 in Ubuntu.  (I recognize that 
Ubuntu != Debian.  However, this is also a problem in Etch that I just 
didn't report earlier, and I think it could be addressed in both distros.)

> $ sudo apt-get install postgresql
>    ...
> Setting up postgresql-client-8.2 (8.2.7-0ubuntu0.7.10) ...
> update-alternatives: unable to make /usr/share/postgresql/8.2/man/man1/dropuser.1.gz.dpkg-tmp a symlink to /etc/alternatives/dropuser.1.gz: No such file or directory

^^^^^^^^^^^^^^^^^^^^^^^

The ^^^^ is color-escaped, which is no good for the symlinking.

I think an appropriate solution would be to unset or export 
GREP_OPTIONS='--color=none' in the beginning of scripts that rely on grep.

Kevin

Message #10 received at 475772@bugs.debian.org (full text, mbox, reply):

From: Colin Watson <cjwatson@debian.org>

To: Kevin Hunter <hunteke@earlham.edu>, 475772@bugs.debian.org

Subject: Re: Bug#475772: dpkg should set GREP_OPTIONS

Date: Sun, 13 Apr 2008 19:08:06 +0100

reassign 475772 general
thanks

On Sat, Apr 12, 2008 at 04:52:47PM -0400, Kevin Hunter wrote:
> I've recently set GREP_OPTIONS='--color=always' in my bashrc.  I do this 
> mainly so that I can see grep's highlighted findings even when viewing 
> through a pipeline, such as with less.  '--color=auto' won't work 
> because it will turn off the color escapes if it's going down the 
> pipeline, which is not what I want when I use less.
> 
> This poses a problem for a lot of scripts, which assume that text coming 
> from their stdin is free from (color) escapes.  For instance, I recently 
> went to install postgresql-client-8.2 in Ubuntu.  (I recognize that 
> Ubuntu != Debian.  However, this is also a problem in Etch that I just 
> didn't report earlier, and I think it could be addressed in both distros.)
> 
> > $ sudo apt-get install postgresql
> >    ...
> >Setting up postgresql-client-8.2 (8.2.7-0ubuntu0.7.10) ...
> >update-alternatives: unable to make 
> >/usr/share/postgresql/8.2/man/man1/dropuser.1.gz.dpkg-tmp a symlink to 
> >/etc/alternatives/dropuser.1.gz: No such file or directory
> 
> ^^^^^^^^^^^^^^^^^^^^^^^
> 
> The ^^^^ is color-escaped, which is no good for the symlinking.
> 
> I think an appropriate solution would be to unset or export 
> GREP_OPTIONS='--color=none' in the beginning of scripts that rely on grep.

It's not clear to me that it's going to be feasible for dpkg to
carefully go around and unset every variable that might affect any
maintainer script. It could take debuild's approach of removing
everything except known-good environment variables, but since it's never
done this to date this would probably break quite a few different
things; for example I suspect it's probably intentional that you can
override the linker with LD_PRELOAD for local testing, and a number of
maintainer scripts probably have local environment variable overrides
for one thing or another (not necessarily a terribly good idea in
official Debian packages, but I can imagine situations where it might be
useful).

It sounds even less feasible for us to change every single script; there
are tens of thousands of the things maintained by at least thousands of
different people even just in Debian, and such a job would take years.
(sudo does sanitise the environment in some modes of operation, but
intentionally not in all.)

Would it not involve less in the way of swimming uphill to use a
solution that affects only your interactive environment, and that
doesn't break scripts? After all, this problem is hardly unique to dpkg
or Debian. Try:

  alias grep='grep --color=always'

-- 
Colin Watson                                       [cjwatson@debian.org]

Message #17 received at 475772@bugs.debian.org (full text, mbox, reply):

From: Kevin Hunter <hunteke@earlham.edu>

To: Colin Watson <cjwatson@debian.org>

Cc: 475772@bugs.debian.org

Subject: Re: Bug#475772: dpkg should set GREP_OPTIONS

Date: Sun, 13 Apr 2008 18:10:31 -0400

At 2:08p -0400 on Sun, 13 Apr 2008, Colin Watson wrote:
> reassign 475772 general

>> I think an appropriate solution would be to unset or export 
>> GREP_OPTIONS='--color=none' in the beginning of scripts that rely on grep.

> [not feasible, *lots* of legacy scripts to fix]

Good point.  I guess the mode I was thinking as I wrote that was more 
along the lines of "start from a known good point".  Fine, it won't 
happen overnight, but it could be entered into a "best practices" thing 
for noob maintainers and whatnot.

For a semi-analogous example, I'm seeing more and more folks build their 
website CSS by starting with a block of rules and selectors that resets 
all CSS to be the same across all browsers.  I think this is very good 
practice.  For reference:

http://snipurl.com/24bfp  [snipplr_com]

I'm not saying fix all packages, but perhaps enter the general mindset 
and let it trickle down.

> [fix your *interactive* environment]
>  alias grep='grep --color=always'

Now see, that's smart!  This fixes the *interactive* environment, and 
leaves scripts to do their own thing.  Nice.  A little tidbit here, a 
bit more there, and sooner or later I'll get my environment perfect.

/me edits his .bashrc

Thanks!

Kevin

Message #22 received at 475772-done@bugs.debian.org (full text, mbox, reply):

From: Osamu Aoki <osamu@debian.org>

To: 475772-done@bugs.debian.org

Subject: Your odd GREP_OPTIONS setting is not package problem

Date: Sat, 26 Apr 2008 16:23:56 +0900

Hi,

(I do not understand why the submitter does not use
GREP_OPTIONS='--color=auto'.)

Anyway, you can break many normal program operations if you set
unreasonable value to environment variables.  This is not just
GREP_OPTION for grep but you can have fun with TAPE or TAR_OPTIONS for
tar. It is only yourself to blame.

Since submitter said "smart" to other fix method, it is best to close
this bug.

Cheers,

Osamu

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