What is hash Linux command?

The Linux hash command allows users to perform fast password hashing using various algorithms such as MD5, SHA-256, and SHA-512.

hash Syntax:

hash [option] [name]

Option	Description
-r	Forget all remembered locations
-t	Display the full pathname of the command, if found
-p	Display the full pathname of the command specified by name, if found

Parameter	Description
name	The name of the command to locate in the hash table

hash filename.txt

Calculates the hash value for the specified file “filename.txt”.

hash -c data.txt.hash

Checks the integrity of the file “data.txt” by comparing its hash value stored in “data.txt.hash”.

echo "Hello World" | hash -a sha256

Calculates the SHA256 hash value for the string “Hello World”.

hash -r ./directory

Recursively computes hash values for all files in the specified directory.

hash -l

Lists all available hash algorithms that can be used with the hash command.

To use the hash command in bash, execute the following command:

hash

To clear the hash table in bash, use the following command:

hash -r

To display the full path of a command using hash in bash, use the following command:

hash <command>

To force the rehashing of the full path to a command in Linux bash, use the following command:

hash -p /new/path/to/command <command>

To show the number of hits for each command in the hash table in bash, use the following command:

hash -l

To enable hashing for a specified command name in Linux bash, use the following command:

hash -p /path/to/command <command>

To disable hashing for a specified command in Linux bash, use the following command:

hash -d <command>

To check the hash table size in bash, use the following command:

hash -t

Used to display or update the current hash table for locating the full pathname of a command.
Helps in managing the efficiency and performance of the shell by reducing the time taken to locate and execute commands.