Find
- The original search solution which is pretty much universal to all
versions of linux.
- The most amount of options.
Locate
- Finds files using a database.
- Faster than find (because it reads from a database).
- Results might be outdated (depending on when the database was updated).
Which
- Is for finding commands rather than files and folders.
- Works by search the PATH for executable files matching the names of the
arguments.