       hash [ -dfmr ] [ name[=value] ] ...
              With no arguments or options, hash  will  list  the
              entire command hash table.

              The  -m  option causes the arguments to be taken as
              patterns (they should be quoted) and  the  elements
              of  the  command hash table matching these patterns
              are printed.

              The -r option causes the command hash table  to  be
              thrown out and restarted.  The -f option causes the
              entire path to be searched, and  all  the  commands
              found  are  added to the hash table.  These options
              cannot be used with any arguments.

              For each name with a corresponding value, put  name
              in  the command hash table, associating it with the
              pathname value.  Whenever name is used as a command
              argument,  the  shell  will try to execute the file
              given by value.  For each name with no  correspond-
              ing  value, search for name in the path, and add it
              to the command hash table, and associating it  with
              the discovered path, if it is found.

              Adding  the  -d  option  causes  hash to act on the
              named directory table instead of the  command  hash
              table.   The remaing discussion of hash will assume
              that the -d is given.

              If invoked without any arguments, and  without  any
              other  options,  hash  -d  lists  the  entire named
              directory table.

              The -m option causes the arguments to be  taken  as
              patterns  (they  should be quoted) and the elements
              of the named directory table  matching  these  pat-
              terns are printed.

              The  -r  option causes the named directory table to
              be thrown out and restarted so that  it  only  con-
              tains  `~'.   The -f option causes all usernames to
              be added  to  the  named  directory  table.   There
              options cannot be used with any arguments.

              For  each name with a corresponding value, put name
              in the named directory table.  The  directory  name
              name  is  then  associated  with the specified path
              value, so that value may be referred to as `~name'.
              For  each  name with no corresponding value, search
              for as a username and as a  parameter.   If  it  is
              found,  it  is  added  to  the named directory hash

              table.
