hash(1) — Commands
NAME
hash − Remembers or reports utility locations
SYNOPSIS
hash [utility]
hash −r
STANDARDS
Interfaces documented on this reference page conform to industry standards as follows:
hash: XCU5.0
Refer to the standards(5) reference page for more information about industry standards and associated tags.
OPTIONS
−rForgets all previously remembered utility locations.
OPERANDS
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.
DESCRIPTION
The 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, hash reports on the contents of the list. This list consists of those utilities named in previous hash invocations that have been invoked, and those invoked and found through the normal command search process. This list includes the path name of each utility in the list of remembered locations for the current shell environment.
NOTES
1.The use of hash with utility names is unnecessary for most applications, but may provide a performance improvement.
2.The effects of hash −r can also be achieved by resetting the value of PATH.
RESTRICTIONS
1.If hash is called in a separate utility execution environment, such as one of the following it will not affect the command search process of the caller’s environment.
nohup hash -r
find . -type f | xargs hash
2.Utilities provided as built-ins to the shell are not reported by hash.
EXIT STATUS
The following exit values are returned:
0Successful completion.
>0An error occurred.
ENVIRONMENT VARIABLES
The following environment variables affect the execution of hash:
LANG
Provides a default value for the internationalization variables that are unset or null. If LANG is unset or null, the corresponding value from the default locale is used. If any of the internationalization variables contains an invalid setting, the utility behaves as if none of the variables had been defined.
LC_ALL
If set to a non-empty string value, overrides the values of all the other internationalization variables.
LC_CTYPE
Determines the locale for the interpretation of sequences of bytes of text data as characters (for example, single-byte as opposed to multibyte characters in arguments).
LC_MESSAGES
Determines the locale that should be used to affect the format and contents of diagnostic messages written to standard error.
NLSPATH
Determines the location of message catalogues for the processing of LC_MESSAGES.
PATH
Determines the location of name.