On Mon, 25 Mar 2013, David Laight wrote:
$ pid=$(sh -c 'ps -oppid -p $$')
$ pid=${pid#PPID }
Although some old versions of sh don't like the space in that pattern.
If you have a ps(1) newer than 2006-10-02, then: pid=$(sh -c 'ps -o ppid= -p $$') --apb (Alan Barrett)