Re: [PLUG] How to find parent in the shell?

["Michael C. Toren" <mct@toren.net>]

On Sun, Jan 04, 2004 at 11:11:19PM -0500, Stephen Gran wrote:
> What I'm looking for is something like $PPID, or maybe $$, but that
> gives me a little more information to work with,

To extract argv[0] of the parent, perhaps you could use:

	awk '{print}' /proc/$PPID/cmdline

Unfortunately, the above command is somewhat deceptive, at least for
mawk version 1.3.3-8, which is the awk implementation that happens to be
installed on my local system.  Based on the output of the following test,
mawk seems to use nul-terminated strings internally, probably the result
of using stdio:

	[mct@ellesmere ~]$ echo -e "foo\0bar"| awk '{print}'
	foo

The net result is that it's easy to extract the first nul-terminated
string of /proc/$PPID/cmdline using awk, but not the second.  I would
normally recommend using perl in a situation like this one, however I
believe the use of perl in Debian init.d scripts is frowned upon?

> and a way to make it be portable across the various implementations.

This is also entirely linux specific.  Or by implementations, did you
mean distributions?

-mct
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