Korn shell question

[Patrick O'Callaghan]

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=

poc