Multiple Installations and Understanding $PATH

Question

I have an older version of Git installed at:

/usr/bin/

I recently downloaded a newer version to:

/usr/local/bin

When I type:

which git

I get the location of the old version. I believe that this is just because /usr/bin/ appears before /usr/local/bin in my $PATH variable and so the older version of git is 'found' first.

To test this, I renamed the older version of git to "git_old". Now when I type:

which git

I get the location of the newer version, as expected. But when I type:

git --version

I get the following error:

-bash: /usr/bin/git: No such file or directory

I'm just wondering why my computer is going back to looking in the old location for Git?

Answer 1

Bash caches the full path to executables so that it doesn't have to look through $PATH every time.

You can see what is in the cache using the hash command:

deltik@node51 [~]$ hash
hits    command
   1    /usr/bin/git

This cache can be cleared with hash -r:

deltik@node51 [~]$ hash -r
deltik@node51 [~]$ hash
hash: hash table empty

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Additional Resources

• How do I clear Bash's cache of paths to executables? on Unix Stack Exchange
• What is the purpose of the hash command? on Unix Stack Exchange
• How to get bash to automatically refresh program locations' cache? on Super User
• Documentation on hash