ctags
Generates an index (or tag) file of language objects found in source files for many popular programming languages.
TLDR
Generate tags for a single file, and output them to a file named "tags" in the current directory, overwriting the file if it exists
$ ctags [path/to/file]
Generate tags for all files in the current directory, and output them to a specific file, overwriting the file if it exists
$ ctags -f [filename] *
Generate tags for all files in the current directory and all subdirectories
$ ctags --recurse
