find and locate.
WHAT find DOES
Walks a directory tree and matches files by criteria.
WHAT THE BASIC FORM IS
find, a starting path, then conditions.
WHAT TO SEARCH BY
Name Type, file or directory Size Modification time Owner Permissions
WHY MODIFICATION TIME IS SO USEFUL
It answers what changed recently, which is the first question after a compromise or a breakage.
WHAT AN EXAMPLE QUESTION IS
Which files under this account changed in the last day?
WHAT THE EXECUTE OPTION DOES
Runs a command on each result.
WHY THAT IS POWERFUL AND DANGEROUS
It applies an action to everything matched, and a wrong pattern applies it widely.
WHAT TO DO FIRST
Run the find without the action, and read the list.
WHAT locate DOES
Searches a prebuilt index, very quickly.
WHAT ITS WEAKNESS IS
The index is periodically rebuilt, so recent files are missing.
WHAT which AND whereis DO
Show where a command lives.
WHY THAT MATTERS
Several versions of a program may exist, and knowing which runs explains odd behaviour.
WHAT TO USE FOR LARGE ACCOUNTS
find with restrictions, to avoid scanning the whole disk.
