ctags - Linux

Overview

ctags is a powerful tool that helps you create a tag file for a codebase, making it easy to navigate and search through codebases. It is commonly used in conjunction with editors and IDEs to facilitate code exploration.

Syntax

ctags [options] [directory] [filenames]

Options/Flags

  • -f, –file=FILE: Specify a custom tag file name.
  • -L, –list-tags: List all tags in the given tag file.
  • -R, –recurse: Recursively traverse directories for code files.
  • -e, –extra=+EXT1,+EXT2,…: Specify additional file extensions to parse.
  • -I, –ignore=+EXT1,+EXT2,…: Ignore files with specific extensions.
  • –exclude=PATTERN: Ignore files/directories matching the given shell-style pattern.
  • -x, –regex=REGEX: Customize the file parsing regex.

Examples

Simple Usage

Create a tag file for all C source files in a directory:

ctags -f my_tags.tags src

Advanced Filtering

Generate a tag file for all PHP files except for those in the "vendor" directory:

ctags -R -I=+vendor -f tags php

Custom File Extension

Include Python script files in the tag file:

ctags -f tags -e=+.py src

Common Issues

  • Missing Tag File: Ensure the specified tag file exists and has write permissions.
  • No Output: Check that the specified directory contains code files in supported languages.
  • Invalid Regex: Verify the regex provided with the --regex option is valid.

Integration

ctags output can be used with:

  • Text editors like Vim, Emacs, and Sublime Text for easy code navigation.
  • IDEs such as IntelliJ, Eclipse, and Visual Studio Code for enhanced code exploration.
  • Code search tools to quickly locate specific symbols or functions.

Related Commands

  • grep
  • find
  • apropos