Support POSIX 1003.1-2001 without XSI extensions (ITS #2667):
Do not use test -a/-o. Use shell features like &&, || or case...esac. Use grep instead of egrep (but not the not-yet-portable Posix variant grep -E). Based on a patch from Paul Eggert.
Do not use test -a/-o. Use shell features like &&, || or case...esac. Use grep instead of egrep (but not the not-yet-portable Posix variant grep -E). Based on a patch from Paul Eggert.