Answer :
In the 'vi' text editor, to save a file and exit from command mode, you use various commands according to the mode you are in. The text editor 'vi' is a screen-oriented text editor originally created for the Unix operating system. Here, we are dealing with command mode operations.
To save and quit a file in 'vi', the correct option is:
D) ZZ
This command is a shortcut in command mode that saves the current changes you've made to a file and exits 'vi'. Here's a bit more detail on how it works:
Command Mode: When you start 'vi', you are typically in command mode. It's in this mode that you can enter commands like ZZ to save and exit.
Saving and Exiting: By pressing the 'Shift' key and then 'Z' twice ('ZZ'), the editor will save all changes made to the file and then exit back to the shell.
Alternate Methods: Another common method (not listed here) is :wq which also writes the changes and quits the editor, but within this particular question context, 'ZZ' is the correct answer choice.
A quick note on the other options:
- A) cw: This is a command used to change a word in the text.
- B) /: This is used for searching within the text file.
- C) ~: This is used to change the case of the character under the cursor.
Understanding these commands can greatly enhance your efficiency in using 'vi' to edit files in a Unix or Linux environment.