find is a Command Line Interfacetool to find files on your filesystem.
General format:
find <directory> -type <type> -print
Useful options:
-size 0 # find empty files
-exec <COMMAND> # Execute a command on every file found
-name '*.txt' # Find files with a name
-iname '*.txt' # Find files with a name
-path '/home/<user>' # Find in a given path
-ipath '/home/<user>' # Find in a given path (case insensitive)
-print0 # print NULL seperated file names (useful for using with `xargs -0`)
-delete # delete the files found
-type <TYPE> # TYPE to search for, f: file, l: symlink, d: directory etc.
-maxdepth <NUM> # Only go down NUM levels deep in directory tree