Linux basic commands

Check size directories

$ du -sh *

Search file

$ sudo find [path] -name "[filename]"

Unzip tar.gz using tar command

$ tar -xvzf filename.tar.gz

f: this must be the last flag of the command, and the tar file must be immediately after. It tells tar the name and path of the compressed file.
z: tells tar to decompress the archive using gzip
x: tar can collect files or extract them. x does the latter.
v: makes tar talk a lot. Verbose output shows you all the files being extracted.

Specify a port with the scp command

$ scp -P 2222 path-file-from username@example.com:~/path-file-destination