[root@x1-6-00-01-4a-05-e6-e4 /]# which
Usage: /usr/bin/which [options] [--] programname [...]
Options: --version, -[vV] Print version and exit successfully.
         --help,          Print this help and exit successfully.
         --skip-dot       Skip directories in PATH that start with a dot.
         --skip-tilde     Skip directories in PATH that start with a tilde.
         --show-dot       Don't expand a dot to current directory in output.
         --show-tilde     Output a tilde for HOME directory for non-root.
         --tty-only       Stop processing options on the right if not on tty.
         --all, -a        Print all matches in PATH, not just the first
         --read-alias, -i Read list of aliases from stdin.
         --skip-alias     Ignore option --read-alias; don't read stdin.
         --read-functions Read shell functions from stdin.
         --skip-functions Ignore option --read-functions; don't read stdin.
[root@x1-6-00-01-4a-05-e6-e4 /]# which ndiswrapper /usr/sbin/ndiswrapper
/usr/bin/which: no ndiswrapper in (/usr/kerberos/sbin:/usr/kerberos/bin:/usr/local/bin:/usr/bin:/bin:/usr/X11R6/bin:/home/laptop/bin)
/usr/sbin/ndiswrapper
[root@x1-6-00-01-4a-05-e6-e4 /]#