How Do I Fix a "Read-Only" Error When I Edit the /etc/fstab File?
Symptom
When you try to edit the /etc/fstab file, the message "readonly" is displayed.
Solution
In the read-only mode, the file cannot be modified. Run the following command to obtain the read and write permissions on the file:
mount -o remount,rw /
After the preceding command is executed, edit the file again.