hash [ -Ldfmrv ] [ name[=value] ] ...
       hash  can  be used to directly modify the contents of the command
       hash table, and the named directory  hash  table.   Normally  one
       would  modify  these tables by modifying one's PATH (for the com-
       mand hash table) or by creating appropriate shell parameters (for
       the named directory hash table).  The choice  of  hash  table  to
       work  on  is  determined by the -d option; without the option the
       command hash table is used, and with the option the named  direc-
       tory hash table is used.

       A  command name starting with a / is never hashed, whether by ex-
       plicit use of the hash command or otherwise.  Such a  command  is
       always found by direct look up in the file system.

       Given  no  arguments,  and  neither the -r or -f options, the se-
       lected hash table will be listed in full.

       The -r option causes the selected hash table to be  emptied.   It
       will  be  subsequently rebuilt in the normal fashion.  The -f op-
       tion causes the selected hash table to be fully  rebuilt  immedi-
       ately.   For  the command hash table this hashes all the absolute
       directories in the PATH, and for the named directory  hash  table
       this  adds all users' home directories.  These two options cannot
       be used with any arguments.

       The -m option causes the arguments to be taken as patterns (which
       should be quoted) and the elements of  the  hash  table  matching
       those  patterns  are  printed.  This is the only way to display a
       limited selection of hash table elements.

       For each name with a corresponding value, put `name' in  the  se-
       lected  hash table, associating it with the pathname `value'.  In
       the command hash table, this means that whenever `name'  is  used
       as  a  command  argument,  the shell will try to execute the file
       given by `value'.  In the named directory hash table, this  means
       that `value' may be referred to as `~name'.

       For each name with no corresponding value, attempt to add name to
       the  hash  table,  checking  what the appropriate value is in the
       normal manner for that hash table.  If an appropriate value can't
       be found, then the hash table will be unchanged.

       The -v option causes hash table entries to be listed as they  are
       added  by  explicit specification.  If has no effect if used with
       -f.

       If the -L flag is present, then each hash table entry is  printed
       in the form of a call to hash.

rehash Same as hash -r.