Edit files on a Linux server with nano and vim

Most server configuration lives in plain text files, so editing over SSH is a core skill. nano is the easiest editor and shows its shortcuts on screen; vim is installed almost everywhere and is fast once you know a handful of keys.

Before you start

• An SSH session (see connect with SSH).
• sudo rights to edit system files under /etc.
• Install the editors if missing: sudo apt install nano vim or sudo dnf install nano vim.

Back up the file first

sudo cp /etc/nginx/nginx.conf /etc/nginx/nginx.conf.bak

Edit with nano

sudo nano /etc/hosts

Type to edit. The bottom bar lists shortcuts, where ^ means Ctrl:

Edit with vim

sudo vim /etc/hosts

vim opens in normal mode, where keys are commands. Press i to enter insert mode and type; press Esc to return to normal mode.

Pick your default editor

Commands such as crontab -e and visudo use your default editor. Set it with export EDITOR=nano in ~/.bashrc, or on Ubuntu run sudo update-alternatives --config editor.

After editing

Test the config before reloading the service, e.g. sudo nginx -t, sudo sshd -t or sudo apachectl configtest, then reload as shown in systemctl and journalctl.

Troubleshooting

• File is read-only / Permission denied on save: you opened it without sudo. In vim you can still save with :w !sudo tee %.
• Swap file found in vim: another session is editing the file or one crashed. Choose (R)ecover or delete the .swp file if nobody else is editing.
• Pasted text gets auto-indented in vim: run :set paste before pasting.

Next steps

• Essential Linux commands cheat sheet
• Edit the sudoers file safely with visudo
• Schedule cron jobs