The search order of the PATH enviroment variable is different under root and non-root user. This can make a different behaivor for shell scripts under user root and non-root user.
PATH root is set as: /sbin:/usr/sbin:/bin:/usr/bin:/usr/X11R6/bin:/usr/local/bin:/usr/local/sbin PATH non-root is set as: /usr/X11R6/bin:/usr/local/bin:/bin:/usr/bin:/usr/games The best soultion would be: PATH for user root: /sbin:/usr/sbin:/usr/local/sbin:/bin:/usr/bin/:/usr/X11R6/bin:/usr/games:/usr/local/bin PATH for non-root user: /bin:/usr/bin/:/usr/X11R6/bin:/usr/games:/usr/local/bin
