Re: Korn shell question

["Don Russell" <fedora@xxxxxxxxxxxxxxxxxxxxx>]

On Tue, Apr 15, 2008 at 4:17 PM, Cameron Simpson <cs@xxxxxxxxxx> wrote:

On 15Apr2008 12:09, Don Russell <fedora@xxxxxxxxxxxxxxxxxxxxx> wrote:
| On Tue, Apr 15, 2008 at 11:08 AM, Patrick O'Callaghan <pocallaghan@xxxxxxxxx>
| 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
| > and work from there.
|
| That looks promising... thanks :-)

Promising, but will work only on Linux. That may be enough for you, but you
shouldn't forget that it's nonportable.

I just tried this on a Linux system... it makes sense... I tried it on a UNIX (AIX) system, and it did not help directly. On UNIX the status file appears to be "raw" binary data that maps to a C structure... could get tricky trying to extract the correct parts.

On Linux, it looks like that decoding is all done and present in human-readable terms. :-)

You can probably make that `cat|grep|cut` into a single `sed` at some
performance benefit.

Another approach is to alter your shell environment to always set and export
an environment variable when starting vi (by invoking vi via a wrapper script
or alias or shell function) and then just checking for it.

Though simple, that's not an option for me.... I can't "wrap" vi...