Various processes use Bourne shell (/bin/sh), which has a long and interesting past and carries some necessity for care, to avoid non-portable constructs. This file lists some of these constructs. Probably there are other accumulations of such tips somewhere on the net (refs welcome!). * For variable ref+assignemnt, use ${VAR-VALUE} -- some implementations also allow ${VAR:-VALUE}, but not all. * In Solaris 2.7 /bin/sh, "set -e -x" assigns "-x" to the current command line. It is better to use "set -ex".