SYNOPSIS
       which [-a] filename ...

DESCRIPTION
       which returns the pathnames of the files (or links) which would be exe-
       cuted in the current environment, had its arguments been given as  com-
       mands  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 exe-
              cutable

       2      if an invalid option is specified