UNIX for Advanced & Expert Users

whatis
apropos

command: command [-pVv] command [arg ...]
    Runs COMMAND with ARGS ignoring shell functions.  If you have a shell
    function called `ls', and you wish to call the command `ls', you can
    say "command ls".  If the -p option is given, a default value is used
    for PATH that is guaranteed to find all of the standard utilities.  If
    the -V or -v option is given, a string is printed describing COMMAND.
    The -V option produces a more verbose description.

$ command -v mkdir
/bin/mkdir

$ command -V mkdir
mkdir is hashed (/bin/mkdir)

$ command -V ls
ls is aliased to `ls -CF --color=never'

$ command -V mag
mag is hashed (/home/drl/bin/mag)

OS, ker|rel, machine: Linux, 2.6.26-2-amd64, x86_64
Distribution        : Debian 5.0.8 (lenny, workstation) 
bash GNU bash 3.2.39
ksh 93s+

$ whence -v whence
whence is a shell builtin

$ type test time
test is a shell builtin
time is a shell keyword

$ which test time
/bin/test
/usr/bin/time

$ type -a test time
test is a shell builtin
test is /bin/test
time is a shell keyword
time is /usr/bin/time