apt - Advanced Package Tool (APT) is a free-software user interface that works with core libraries to handle the installation and removal of software on Debian and Debian-based Linux distributions.

systemd status - determine the status of a service

nano - a simple terminal-based text editor

lsb_release - print distribution specific information

openssh-server - collection of tools for remotely controlling networked computers. Example:

sudo apt install openssh-server
sudo systemctl enable --now ssh

pipeline ‘|’ or ‘|&’ - a sequence of one or more commands separated by one of the control operators.

grep - grep searches one or more input files for lines containing a match to a specified pattern. Example:

php -m | grep -i mysql

groupadd - create a new group

useradd - create a new user or update default new user information

chown - change file owner and group

chmod - change access permissions

> - before a command is executed, its input and output may be redirected using a special notation interpreted by the shell.

find - find files. Example:

 sudo find / -type f -name "dovecot-sql.conf" 2>/dev/null
  • find / — search starting from the root /, so essentially the whole filesystem.
  • -type f — search only for files.
  • -name "dovecot-sql.conf" — look for exactly this filename.
  • 2>/dev/null — redirection to hide permission-denied and other error messages.

wget - software package for retrieving files using HTTP, HTTPS, FTP and FTPS

tar - provides the ability to create and extract tar archives

mv - move (rename) files

composer - a dependency manager for PHP

rm - remove files or directories

ln - make links between files

journalctl - print log entries from the systemd journal