You can add extra features to gedit by enabling plugins. A plugin is a supplementary program that enhances the functionality of an application. Plugins add new items to the gedit menus for the new features they provide. Several plugins come built-in with gedit, and you can install more. The following plugins come built-in with gedit:
- Change Case allows you to change the case of the selected text.
- Document Statistics shows the number of lines, words, and characters in the document.
- External Tools allows you to execute external commands from gedit.
- File Browser allows you to browse your files and folders in the side pane.
- Indent Lines adds or removes indentation from the selected lines.
- Insert Date/Time adds the current date and time into a document.
- Modelines allows you to set editing preferences for individual documents, and supports Emacs, Kate and Vim-style modelines.
- Python Console allows you to run commands in the python programming language.
- Snippets allows you to store frequently-used pieces of text and insert them quickly into a document.
- Sort arranges selected lines of text into alphabetical order.
- Spell Checker corrects the spelling in the selected text, or marks errors automatically in the document.
- Tag List lets you insert commonly-used tags for HTML and other languages from a list in the side pane.
- User Name inserts the username of the current user into the document.
See how to add add Python / C++ autocomplete support to gedit text editor.Read answer to: "gedit: Add Python / C++ Autocomplete Support"