Basic commands

Here is a reminder of the basic Linux commands and actions we will frequently use on the Linux terminal.
Each command is validated with Enter.

Login / logout

From a Windows command prompt, or from a MacOS or Linux terminal, remotely login with the user leguellec into the server grav.howto.ovh using ssh:

ssh leguellec@grav.howto.ovh

Logout:

exit

While logged in, temporarily switch to another user called berthier:

su - berthier

Update / upgrade

Collect the latest versions of installed software with apt update, install these collected updates with apt upgrade, accept by default the installation of upgrades with -y and chain the commands one after the other with &&:

sudo apt update && sudo apt upgrade -y

Reboot / shutdown

Immediately reboot the server:

sudo reboot

Immediately shutdown the server:

sudo shutdown -h now

Physical status

Visual tool to check physical health, memory status, load and services running:

htop

Check disk space used and available on the root directory /:

df -h /

Detailed check of disk space used by /home sub-directory:

sudo du -c -h -d 1 /home 2>/dev/null

Search for a file named filename.ext in /usr sub-directory, and only display any successful find

result=$(find /usr -name "filename.ext" 2>/dev/null)
if [ -n "$result" ]; then
    echo "$result"
fi

Nano file editor

• Select text: move the cursor at the beginning of the section to select with keyboard arrows, use Alt+a and move the cursor at the end of the section
• Cut text Ctrl+k
• Paste text Ctrl+u
• Undo Alt+u
• Save file Ctrl+s
• Quit nano Ctrl+x