hash

SYNOPSIS
       hash [utility...]

       hash -r


DESCRIPTION
       The  hash  utility  shall  affect the way the current shell environment
       remembers the locations of utilities  found  as  described  in  Command
       Search  and  Execution . Depending on the arguments specified, it shall
       add utility locations to its list of remembered locations or  it  shall
       purge  the  contents  of  the list. When no arguments are specified, it
       shall report on the contents of the list.

       Utilities provided as built-ins to the shell shall not be  reported  by
       hash.

OPTIONS
       The  hash  utility  shall  conform  to  the  Base Definitions volume of
       IEEE Std 1003.1-2001, Section 12.2, Utility Syntax Guidelines.

       The following option shall be supported:

       -r     Forget all previously remembered utility locations.


OPERANDS
       The following operand shall be supported:

       utility
              The name of a utility to be searched for and added to  the  list
              of  remembered  locations.  If  utility  contains  one  or  more
              slashes, the results are unspecified.


STDIN
       Not used.

INPUT FILES
       None.

ENVIRONMENT VARIABLES
       The following environment variables shall affect the execution of hash:

       LANG   Provide a default value for the  internationalization  variables
              that  are  unset  or  null.  (See the Base Definitions volume of
              IEEE Std 1003.1-2001, Section  8.2,  Internationalization  Vari-
              ables  for the precedence of internationalization variables used
              to determine the values of locale categories.)

       LC_ALL If set to a non-empty string value, override the values  of  all
              the other internationalization variables.


       PATH   Determine the location of utility, as described in the Base Def-
              initions volume of IEEE Std 1003.1-2001, Chapter 8,  Environment
              Variables.


ASYNCHRONOUS EVENTS
       Default.

STDOUT
       The  standard output of hash shall be used when no arguments are speci-
       fied. Its format is unspecified, but  includes  the  pathname  of  each
       utility in the list of remembered locations for the current shell envi-
       ronment. This list shall consist of those utilities named  in  previous
       hash  invocations that have been invoked, and may contain those invoked
       and found through the normal command search process.

STDERR
       The standard error shall be used only for diagnostic messages.

OUTPUT FILES
       None.

EXTENDED DESCRIPTION
       None.

EXIT STATUS
       The following exit values shall be returned:

        0     Successful completion.

       >0     An error occurred.


CONSEQUENCES OF ERRORS
       Default.

       The following sections are informative.

APPLICATION USAGE
       Since hash affects the  current  shell  execution  environment,  it  is
       always provided as a shell regular built-in. If it is called in a sepa-
       rate utility execution environment, such as one of the following:


              nohup hash -r
              find . -type f | xargs hash

       it does not affect the command search process of the caller's  environ-
       ment.

       The  hash  utility  may  be  implemented as an alias-for example, alias
       -t -, in which case utilities found through normal command  search  are
       not listed by the hash command.
       None.

RATIONALE
       None.

FUTURE DIRECTIONS
       None.

SEE ALSO
       Command Search and Execution

COPYRIGHT
       Portions of this text are reprinted and reproduced in  electronic  form
       from IEEE Std 1003.1, 2003 Edition, Standard for Information Technology
       -- Portable Operating System Interface (POSIX),  The  Open  Group  Base
       Specifications  Issue  6,  Copyright  (C) 2001-2003 by the Institute of
       Electrical and Electronics Engineers, Inc and The Open  Group.  In  the
       event of any discrepancy between this version and the original IEEE and
       The Open Group Standard, the original IEEE and The Open Group  Standard
       is  the  referee document. The original Standard can be obtained online
       at http://www.opengroup.org/unix/online.html .



IEEE/The Open Group                  2003                              HASH(P)