NAME
       which - locate a command
SYNOPSIS
       which [-a] filename ...
DESCRIPTION
       which  returns  the  pathnames  of  the files (or links) which would be
       executed in the current environment, had its arguments  been  given  as
       commands  in  a  strictly  POSIX-conformant  shell.   It  does  this by
       searching the PATH for executable  files  matching  the  names  of  the
       arguments. It does not follow symbolic links.
OPTIONS
       -a     print all matching pathnames of each argument
EXIT STATUS
       0      if all specified commands are found and executable
       1      if  one  or  more  specified  commands  is  nonexistent  or  not
              executable
       2      if an invalid option is specified