On Wed, Apr 16, 2008 at 10:37 AM, Don Russell
<fedora@xxxxxxxxxxxxxxxxxxxxx> wrote:
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> On Wed, Apr 16, 2008 at 8:44 AM, Patrick O'Callaghan <pocallaghan@xxxxxxxxx> wrote:
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> > On Wed, 2008-04-16 at 10:41 -0400, Bill Davidsen wrote:
> > > Patrick O'Callaghan wrote:
> > > > On Tue, 2008-04-15 at 10:49 -0700, Don Russell wrote:
> > > >> How can I tell, from a Korn shell script, if the script is running in
> > > >> a vi sub-shell?
> > > >>
> > > >> I have a script that has a problem when run from a vi subshell, and
> > > >> I'd like to check for that condition and just issue an error message.
> > > >> (I know that's not the solution to the problem, but the thing that
> > > >> fails is being replaced, so this is a temporary "fix")
> > > >
> > > > Try:
> > > >
> > > > ls -l /proc/`cat /proc/$$/status|grep PPid|cut -f2`/exe
> > >
> > > What on Earth are you doing here?
> > > 1) unless you have some reason to doubt the value of $PPID, you are just
> > > making this look complex
> > > 2) if this is a login shell, you will not have permission to read the
> > > exe symbolic link.
> > > 3) you probably just want to see if /proc/$PPIC/cmdline matches vi
> >
> > Duh, yes. The OP wants to know if his script is being executed from
> > 'vi'. That's one way to do it. You're right about the permissions of
> > course, my bad, but using $PPID doesn't change that in the script.
> >
> > Here's a better one:
> >
> > ps -p $PPID -o comm=
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> That's GREAT! It's exactly what I need.... and bonus points for it working on other platforms too ;-)
I spoke too soon... I had to tweak it a little.... since running the
script starts a new shell, it's not enough to look at the parent... I
have to go back a generation further to look at the Grand Parent
PID...
Thus, in the script that cares about such things...
GPPID=`/usr/bin/ps -p $PPID -oppid=`
if [[ "LOGINSHELL" != `/usr/bin/ps -p $GPPID -o comm=` ]]; then
print "$0 not allowed from sub-shell" >&2
exit 1
fi
Of course the LOGINSHELL literal could be system specific...
