#!/bin/sh set -e removes () { rm -f -- "$vardir/snap-mount" "$vardir/snap-device" } vardir="$2" case "$#.$1" in 2.drop) removes ;; 4.snap) removes ln -s -- "$3" "$vardir/snap-device" ln -s -- "$4" "$vardir/snap-mount" ;; *) cat >&2 <<'END' usage: .../nosnap snap VARDIR DEV MOUNT .../nosnap drop VARDIR END exit 1 ;; esac