ctags command in Linux with examples

Last Updated : 14 Oct, 2024

The ctags command in Linux is commonly used with classic editors such as vi or vim to create an index or tags file for source code. This allows quick navigation across files, enabling users to jump to function definitions or references. ctags generates a cross-reference file that lists various source objects (functions, variables, etc.) in human-readable language files, facilitating efficient code navigation.

vi/vim can then refer to these tags index files to allow you to follow references. Basically, this command generates the tag files for the source code. It is also used to create a cross-reference file that lists and contains information about the various source objects found in a set of human-readable language files.

Syntax

ctags [options] [file(s)]

Basic Example

To generate a tags file for all source files in a directory, you can use the basic command:

ctags -R *

This recursively generates a tags file for all files in the current directory.

Key Options of the ctags command

--help:

It will print the general syntax of the command along with the various options that can be used with the ctags command as well as gives a brief description about each option.

Options	Description
ctags -a	This option used to append the tags to an existing tag file. Equivalent to --append. [Ignored with -e]
ctags -B	This option used for backward searching patterns (e.g. ?regexp?). [Ignored with -e]
ctags -e	This option used for output a tag file for use with Emacs. If this program is being executed by the name etags, this option is already enabled by default.
tags -F	This option used for searching patterns (e.g. /regexp/)(default). [Ignored with -e]
ctags -i	This option is similar to the --c-types option and is retained for all the compatibility with earlier versions.
ctags -n	This option is Equivalent to --excmd=number.
ctags -N	This option is Equivalent to --excmd=pattern.
ctags -o	This option is Equivalent to -f tagfile.
ctags -p	This option is Used path as the default directory for each supplied source file, unless the source file is already specified as an absolute path.
ctags -R	This option is Equivalent to --recurse=yes.
ctags -u	This option is Equivalent to --sort=no (i.e. "unsorted").
ctags -V	This option Enables the verbose mode. This prints out a brief message describing that what action is being taken for each of the file considered by ctags.

ctags with Vim:

cd to the folder of your choice where your file is located:

Example:

cd /home/algoscale/Desktop/pers/angularapp

Run ctags recursively over the entire folder of your choice to generate the tags file

Now run this command:

ctags -R *

To search for a specific tag and open the output in Vim to its definition, run the following command in your shell:

vim -t "tag"

Example:

vim -t title

As a result this screen pops up with the matching result: Result

Conclusion

The ctags command is a powerful tool for developers working with large codebases, especially in editors like vi, vim, or Emacs. It simplifies the process of navigating code by creating an index of tags that can be quickly referenced to jump between function definitions, classes, or other symbols.

rahulkumarmandal

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