hash

Show command hash table

$ hash

$ hash -r

$ hash -p [/usr/local/bin/mycommand] [mycommand]

$ hash -d [command]

$ hash -t [command]

hash [options] [name...]

hash is a shell built-in that manages the hash table of recently executed commands. The shell uses this table to remember the full paths of commands, avoiding repeated PATH searches.
When a command is executed, the shell stores its path in the hash table. Subsequent invocations use the cached path, improving performance.

$ # View hash table
hash

# Clear after installing new software
hash -r

# Check where a command is hashed
hash -t python

# List all hashed commands
hash -l

-r

Clear hash table.

Add path for name.

Delete name from hash.

Print path for name.

List in reusable format.

Shell built-in; behavior varies by shell. Hash becomes stale if commands move. Use hash -r after PATH changes or software installation. Only affects current shell session.

The hash command has been part of Unix shells since the Bourne shell. It provides manual control over the command path caching mechanism that shells use for performance.

type(1), which(1), command(1)