Bash / Shell

Directories

The location of the current/working directory can be known with pwd.
The creation of a new directory is done with mkdir -p <path> or mkdir <name> (in relative mode).
The change of the working directory is realized with cd <path> or cd <name>.
See also rmdir <path> and rm -rf <path> for suppression, cp -R <old> <new> for copy, and mv <old> <new> for displacement.

Files

A new file can be created in various ways: touch <name>, echo "content" > <name>, cat > <name> followed by CTRL+C when finished, vim <name>, etc.
The content of a text file can be printed with the cat <name> command.

Softwares

The installation of a new tool requires admin privileges (also called super user), and an installation tool is apt:

sudo apt update
apt search ^gcc$
sudo apt install gcc

Nb. Info about the C compiler gcc can be obtained with:

gcc   --help
which gcc # /usr/bin/gcc
ldd   /usr/bin/gcc
file  /usr/bin/gcc

Nb. The /usr/bin directory must be added to the PATH variable.