Linux commands
Software and users#
Installing and updating (apt)#
| Command | Does |
|---|---|
sudo apt update |
Refresh the list of available software (changes nothing) |
apt list --upgradable |
What could be updated |
sudo apt upgrade |
Install the updates |
sudo apt install NAME |
Install a program |
sudo apt remove NAME |
Uninstall it (keeps its settings) |
sudo apt purge NAME |
Uninstall it and its settings |
sudo apt autoremove |
Remove leftovers nobody needs |
apt search WORD |
Find a package |
apt show NAME |
Details of a package |
dpkg -l | grep NAME |
Is it installed, which version? |
command -v NAME |
Where a command lives (empty = not installed) |
ls /var/run/reboot-required |
Exists = an update needs a restart |
Could not get lock
Automatic updates are running. Wait a few minutes. Don't delete lock files.
Accounts#
| Command | Does |
|---|---|
whoami / id |
You, and your groups |
getent passwd |
All accounts (most are system accounts) |
getent group sudo |
Who is an administrator |
sudo adduser NAME |
New normal user (asks for a password) |
sudo adduser --system --group --no-create-home --shell /usr/sbin/nologin NAME |
New locked service account (like ai) |
sudo usermod -aG sudo NAME |
Make someone an administrator (-aG = add to group; without a it replaces all groups) |
sudo usermod -aG GROUP NAME |
Add to any group (log out and in to take effect) |
sudo gpasswd -d NAME GROUP |
Remove from a group |
passwd |
Change your own password |
sudo passwd -l NAME |
Lock an account's password |
sudo deluser NAME |
Delete an account (keeps their files) |
Samba (file sharing) accounts#
| Command | Does |
|---|---|
sudo smbpasswd -a NAME |
Give a user a file-sharing password |
sudo pdbedit -L |
List file-sharing users |
sudo smbpasswd -x NAME |
Remove a user from file sharing |
testparm -s |
Check /etc/samba/smb.conf for mistakes |
Time and restarts#
| Command | Does |
|---|---|
date |
Current date and time |
timedatectl |
Time zone and whether the clock is synchronised |
sudo reboot |
Restart |
sudo poweroff |
Shut down (someone must press the power button to start it again) |
sudo shutdown -r +10 |
Restart in 10 minutes (sudo shutdown -c cancels) |