Create a new user belongs “admin” group called ‘user1′

useradd -c "Name Surname " -g admin -d /home/user1 -s /bin/bash user1

There is a simpler command too…

useradd user1

Show space used by deb packages installed sorted by size (ubuntu, debian and like)

dpkg-query -W -f='${Installed-Size;10}t${Package}n' | sort -k1,1n

Rename a group

groupmod -n new_group_name old_group_name

Set date and time - MonthDayhoursMinutesYear.Seconds

date 041217002007.00

Show the calendar of 2008

cal 2008

Show interrupts

cat /proc/interrupts

show file(s) swap

cat /proc/swaps

This command removes the SVN data from a folder.

find -name .svn -exec rm -rf {} \;

Show configuration of an ethernet network card

ifconfig eth0

Use this command to download numbered content…

for ((i=1; i<9; i++)) ; do  wget "http://www.example.com/$i.txt" ; done