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)