[oclug] Starting an X Windows term

[Joe Burpee]

On 01/08/29 02:02:50, Gilles J. Seguin wrote:
> Joe Burpee wrote:
> > On 01/08/28 21:30:53, Gilles J. Seguin wrote:
> > > ~/.bashrc by default is not source as a personal file if shell is
> > > interactive.
> > Really?  News to me.  Cf man bash.
> 
> When  bash is invoked as an interactive login shell, or as
> a non-interactive shell with the --login option, it  first
> reads and executes commands from the file /etc/profile, if
> that file exists.  After reading that file, it  looks  for
> ~/.bash_profile,  ~/.bash_login,  and  ~/.profile, in that

OK.  I was really thinking of the 2nd para after that:

"When an interactive shell that is not  a  login  shell  is
started,  bash reads and executes commands from ~/.bashrc,
if that file exists.  This may be inhibited by  using  the ..."

My point was that the question is really login-vs-non-login rather
than interactive-vs-noninteractive, but I guess that's not entirely
true.  This stuff always makes my head ache; then of course there's
bash-vs-sh, posix, etc., etc.  8-[

> ~ $ su -
> Password: 
> ~ # cat >> .bashrc
> echo "SHLVL is:$SHLVL"
> ^D
> ~ # echo $SHLVL
> 1
> ~ # exit
> ~ $ su -
> Password: 
> SHLVL is:1
> ~ #
> 
> OK, gets it
> 
> Which test are you suggesting.

Now you've got me.  I guess it depends on what you want to do.  To some
extent I avoid this test by keeping login-type stuff out of bashrc.
(Similarly, IMO aliases do not belong in profile.d/, but I guess I'm
fussy; anyway it just doesn't make practical sense to keep on sourcing
all that stuff.)

An alternative test for a login shell could be [ -z "${0##-*}" ] or
`case "$0" in -*) ...'; however it's uglier, and basically equivalent to
the SHLVL test.

For things like Patrick's problem /tmp/.X*-lock is relevant.  There are
also other X-related situations where $DISPLAY is not enough.  E.g.  I
sometimes want to know if a script has been invoked from a gui app like
nedit or gvim, vs a console app (vim, mutt, etc.) under an "xterm".  So
I look at $TERM, which seems to work.

/etc/bashrc also checks $TERM.  (I notice it misses TERM=rxvt.)  But
then I also want to know whether it's the *first* xterm started under
xinit.

The login question looks a bit like the "first xterm" question?  You
don't really want to know whether you're in a login shell; you probably
want to know whether you're in the *first* (login) shell after init has
just wrapped up a runlevel change (and not to runlevel 5).  I don't
think init exports anything in the environment to tell you this.  But
there are easy ways to do it: e.g. touch&rm in rc.local and profile.
And there's always the source code.

Sorry for the non-answer Gilles.  I guess I'm asking slightly different
questions from the one you were asking.

Joe