# demo for negation ('!') before an [ ] expression. This should work # in POSIX shells, and seems to work in busybox sh BusyBox v1.21.1 # (Ubuntu 1:1.21.0-1ubuntu1), too $ busybox sh -c 'if [ -f asdsad ] ; then echo hi ; else echo ho ; fi' ho $ busybox sh -c 'if ! [ -f asdsad ] ; then echo hi ; else echo ho ; fi' hi