Cmd that used a lot but always forget

Compress or uncompress

# compress
tar cvzf cmprssd.tar.gz cmprssd/

To unpack or extract a tar file, type:

tar -xvf file.tar

REF: tar-extract-linux
To save disk space and bandwidth over the network all files are saved using compression program such as gzip or bzip2. To extract / unpack a .tar.gz (gzip) file, enter (note -z option):

tar -xzvf file.tar.gz

To extract / unpack a .tar.bz2 (bzip2) file, enter (note -j option):

tar -xjvf file.tar.bz2

To extract .rar

sudo apt install unrar
unrar x file.rar

chmod(change to user permission)

sudo chmod -R 777 "target_dir_name"