As system administrator, I have needed to edit configuration files of some services such as DNS (Domain Name System), LDAP (Lightweight Directory Access Protcol) and etc.
The editor I was using frequently was nano and rarely I used pico. All those editors were used on Ubuntu. When I decided to fit in CentOS, I noticed that I had to install package nano. But I did not want to! I wanted to vary and then I searched and found editor Vi (also it is equal to Vim, although Vim has more features than Vi). I confess, at first time, it was very confused. I did not know what commands to edit file and much less how to save the changes and exit. So I googled and found some commands useful to edit files.
Hereafter, you will see a list of commands to Vi/Vim editor:
|:wq||Save the file and exit|
|:w||Save the file|
|:q||Quit and Vi/Vim refuses to exit if any changes was made|
|:!q||Quit without changes to save|
|:a||Append after cursor|
|:i||Insert after cursor|
|ESC||Exit insert/overwrite mode and go back to command mode|