There are 3 commands to directly manipulate the selection of text in the buffer (even if the selection is of size 1):
- Delete - just remove the text from the buffer
- Cut - remove the text from the buffer and insert it into a cut history
- Paste - put the text in the buffer from the cut history
Normally you would want to cut the text instead of deleting so that it is saved in the history and can be later used for insertion.
After pasting the text there's another command Paste-Cycle which changes the inserted text to the older entry in the cut history.
Clipboard integration is active by default but it can be deactivated.
Each expansion/detraction of the selection with the size of more than 1 also copies this text to the "primary" selection of the system if that selection is supported. On X system this selection can be pasted to other applications by clicking a mouse middle button.
Delete command does not interact with the system clipboard.
Cut command also puts the text into the "clipboard" selection of the system. This selection can be normally inserted with the Ctrl-v shortcut.
Paste command first checks the "clipboard" selection of the system, and if there's text present, it is inserted to the buffer. If there's none, then the text is inserted from the cut history.