To test that the param susbtitution in "$@""${v%*/}" is ignored (on a command line or in an assignment): $ dash -c 'v=1/2; w="$@""${v#*/}"; echo "$@""${v#*/}" "$w"' Note that the quoting has to be around each variable, that the first has to be $@ and that the bug occurs with %, %%, #, or ## substring processing. Adding a string in between the 2 required vars does not change the behaviour: $ dash -c 'v=1/2; echo "$@"s$u"s${v#*/}"' except by adding a string, even empty, inside the quoting of $@: $ dash -c 'v=1/2; echo "$a$@""${v#*/}"' Regards -- G.raud Meyer graud@gmx.com