HASH(1) User Commands HASH(1)

NAME

hash, rehash, unhash, hashstat - evaluate the internal hash table of the
contents of directories

SYNOPSIS

/usr/bin/hash [utility]


/usr/bin/hash [-r]


sh
hash [-r] [name]...


csh
rehash


unhash


hashstat


ksh
hash [name]...


hash [-r]

DESCRIPTION

/usr/bin/hash
The /usr/bin/hash utility affects the way the current shell environment
remembers the locations of utilities found. Depending on the arguments
specified, it adds utility locations to its list of remembered locations
or it purges the contents of the list. When no arguments are specified,
it reports on the contents of the list. The -r option causes the shell to
forget all remembered locations.


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

sh
For each name, the location in the search path of the command specified
by name is determined and remembered by the shell. The -r option to the
hash built-in causes the shell to forget all remembered locations. If no
arguments are given, hash provides information about remembered commands.
The Hits column of output is the number of times a command has been
invoked by the shell process. The Cost column of output is a measure of
the work required to locate a command in the search path. If a command is
found in a "relative" directory in the search path, after changing to
that directory, the stored location of that command is recalculated.
Commands for which this will be done are indicated by an asterisk (*)
adjacent to the Hits information. Cost will be incremented when the
recalculation is done.

csh
rehash recomputes the internal hash table of the contents of directories
listed in the path environmental variable to account for new commands
added.


unhash disables the internal hash table.


hashstat prints a statistics line indicating how effective the internal
hash table has been at locating commands (and avoiding execs). An exec is
attempted for each component of the path where the hash function
indicates a possible hit and in each component that does not begin with a
'/'.

ksh
For each name, the location in the search path of the command specified
by name is determined and remembered by the shell. The -r option to the
hash built-in causes the shell to forget all remembered locations. If no
arguments are given, hash provides information about remembered commands.

OPERANDS

The following operand is supported by hash:

utility
The name of a utility to be searched for and added to the
list of remembered locations.

OUTPUT

The standard output of hash is used when no arguments are specified. Its
format is unspecified, but includes the pathname of each utility in the
list of remembered locations for the current shell environment. This list
consists 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.

ENVIRONMENT VARIABLES

See environ(7) for descriptions of the following environment variables
that affect the execution of hash: LANG, LC_ALL, LC_CTYPE, LC_MESSAGES,
and NLSPATH.

PATH
Determine the location of utility.

EXIT STATUS

The following exit values are returned by hash:

0
Successful completion.


>0
An error occurred.

ATTRIBUTES

See attributes(7) for descriptions of the following attributes:


+--------------------+-----------------+
| ATTRIBUTE TYPE | ATTRIBUTE VALUE |
+--------------------+-----------------+
|Interface Stability | Standard |
+--------------------+-----------------+

SEE ALSO

csh(1), ksh(1), sh(1), attributes(7), environ(7), standards(7)


July 17, 2002 HASH(1)