A list of usefull commands
User management: # create a user USERNAME=foo useradd $USERNAME # reset password USERNAME=foo passwd $USERNAME # add an existing user to a group USERNAME=foo GROUP=www usermod -a -G $GROUP $USERNAME cat /user/group # remove user USERNAME=foo userdel $USERNAME # add a user to a group USERNAME=foo GROUP=www-data usermod -a -G $GROUP $USERNAME Archive: # Create an archive OUTPUT=archive.tar.gz INPUT=folder tar -zcvf $OUTPUT $INPUT # Extract archive OUTPUT=folder INPUT=archive.tar.gz tar -zxvf $INPUT -C $OUTPUT Utilities: # disk usage df -h # find out who is taking too much place du -hsx /* | sort -rh network: IP_TO_CHECK=0.0.0.0 nmap -PN $IP_TO_CHECK GIT: # change commit timestamp LC_ALL=C GIT_COMMITTER_DATE="$(date)" git commit --amend --no-edit --date "$(date)"