adduser username
addgroup groupname
usermod -a -G <groups seperated by commas> <user>
uname -a
#kernel version
uname -r
cat /proc/version
# OS version
lsb_release -a
# Listening ports
netstat -tulpn
id
groups # admin can read logs on /var/log
sudo -l
ps -aux # search for root processes
# see EoP
free # memory
top # process / CPU
# Zip
unzip myzip.zip
# Rar
unrar x archive.rar
# Gunzip
gzip -d filename.gz
gunzip -k filename.gz //-k keep (don't delete) original file .gz
zcat filename.gz > filename
# Bzip2
bzip2 -d filename.bz2 // This command will not preserve original archive file
bzip2 -dk filename.bz2 // To preserve the original file
# Tar
tar xvf file.tar
# Tar + Gzip
tar -xzvf archive.tar.gz
# Tar + Bz2
tar -xjvf archive.tar.bz2
# Tar + Xz
tar -xJvf archive.tar.xz
