You opened a file with `vi -R /etc/motd`, so the editor's `readonly` option is set. You then decide the file does need changing, make your edits, and `:w` is refused with a message that the readonly option is set. Your account does have permission to write the file. Which command writes it anyway?
LPIC-1 Exam 101-500, objective 103. GNU and Unix commands medium
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How these questions are written — where each question comes from, what the verification ledger records, and what happens when one is found wrong.
The options
Correct :w!
Correct. A trailing `!` on the ex write command overrides the editor's own readonly guard and writes the file. vim(1) states this for the -R option: if you do want to overwrite the file, add an exclamation mark to the Ex command, as in `:w!`.
Not correct :q!
Wrong, and it loses the work. `:q!` quits and discards every unsaved change in the buffer.
Not correct :wq
Wrong. This is the same unforced write that has already been refused, with a quit appended; without the `!` the readonly option still blocks it. `:wq!` would have worked.
Not correct ZZ
Wrong. `ZZ` is the command-mode shortcut for write-and-quit, so it meets exactly the same refusal as `:wq`.
Why
In ex commands a trailing exclamation mark means force: `:w!` writes over the editor's readonly objection, `:q!` quits over its unsaved-changes objection. The readonly option is the editor's own caution — set by the -R option, by starting the editor as `view`, or automatically when the file carries no write permission for you — and `!` overrides that flag. What `!` cannot override is the kernel: if the filesystem permissions genuinely deny the write, `:w!` fails too, with an error about not being able to open the file for writing.
Where this comes from
- Cited
- manual page vim(1)
Practise this
Reading one question is not practice. The trainer will draw a short set from objective 103 and space the ones you get wrong.
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