How to capture all the environment variables from shell?

[Cameron Simpson]

On 10Aug2010 10:07, Steven W. Orr <steveo at syslang.net> wrote:
| On 8/2/2010 4:33 AM, Thorsten Kampe wrote:
| > * Tim Chase (Mon, 26 Jul 2010 21:42:24 -0500)
| >> On 07/26/10 21:26, Steven W. Orr wrote:
| >>> Please! Never export anything from your .bashrc unless you
| >>> really know what you're doing. Almost all exports should be
| >>> done in your .bash_profile
| >>
| >> Could you elaborate on your reasoning why (or why-not)?  I've 
| >> found that my .bash_profile doesn't get evaluated when I crank up 
| >> another terminal window, while my bashrc does.  Thus I tend to 
| >> put my exports in my ~/.bashrc so they actually take effect in my 
| >> shell...
| > 
| > ~/.bash_profile is only evaluated for login shells and ~/.bashrc only 
| > for non-login shells. Thus it's recommended to keep ~/.bash_profile 
| > empty (except a source statement for .bashrc) and put all your settings, 
| > aliases, exports, etc. in .bashrc.
| 
| Sorry. Dead wrong. Please reread the above comment I wrote. If you set your
| environment variables in the .bashrc then you completely lose the ability of
| environment variables to be inherited by sub-shells. Again, envvars should be
| set in the .bash_profile, most everything else should be set in the .bashrc, and
| the .bashrc should be sourced into the .bash_profile to solve the problem that
| you thought you were solving.
| 
| After that, and again, be aware that the .bashrc alone is executed for login
| shells *which are not interactive*. for example:
| 
| ssh somemachine 'echo Hello'
| 
| This command will *not*  go through the .bash_profile but it will go through the
| .bashrc.

No, only interactive shells use the .bashrc.

Still, you're quite right that envvars belong in the .bash_profile.
.bashrc is for trivial setup stuff relevant only to interactive shells
(for example history settings and interactive aliases).

| This means that for cases like this, we want to check to see if the
| bash process is interactive or not inside the .bashrc and then do the right thing.
| 
| ========<Inside your .bashrc>=======
| [[ -z "$PS1" ]] && setPATHHere
| ========<EOInside your .bashrc>=======

This is Very Wrong. (RedHat do this test - it is bogus - if I set $PS1
in my profile it breaks badly.) Instead, test $-:

  case $- in *i*) echo INTERACTIVE ;; *) echo BATCH ;; esac

| This is not needed for the above degenerate case, but it is needed if the
| command in question is kept in a directory that you normally find in a place
| that is part of your personal login PATH. E.G., If myprog lives in ~/bin then
| 
| ssh somemachine myprog
| 
| will fail unless you use the above construct.
| 
| Hopefully, I'll only have to re-explain this another google times...

"googol", surely?

The reason .bashrc gets overused for envars, aside from ignorance and
propagated bad habits, is that in a GUI desktop the setup sequence is
often a bit backwards. A conventional terminal/console login means you
get a login shell that sources your .{bash_}profile. And from there one
would start a GUI and all the .profile stuff has been run Once, as it
should be. But when the login itself is a GUI the various terminals get
started _before_ the .profile stuff gets sourced, because the terminal
is started by the desktop manager. Once common "fix" for this is to
make all new terminals run login shells. Ugh, but it does work. But it
they're not login shells, people stuff everything into their .bashrc
because the .profile doesn't get sourced. And so the common awful setup
you're bemoaning.

Cheers,
-- 
Cameron Simpson <cs at zip.com.au> DoD#743
http://www.cskk.ezoshosting.com/cs/

For us, Zettai Zetsumei Toshi is an allegory for relations between the sexes,
and it works especially well at this because we don't speak Japanese. She
will say things, and we have no idea what the hell is going on, and then
we'll select from a list of responses, but we have no idea which one is the
right one, and then they're all wrong. It works on a lot of levels.
- Tycho @ _Penny_Arcade_