How to send a message to another user

To send a message to another user logged in the system,type


$ write username
(your message) ctrl+d 

How to stop receving messages from other user's

To stop receving messages from other user's

   
    $ mesg n


To allow messages from other user,type


    $ mesg y

How to display and use the last command you entered in your system

To display and use the last command you entered


    $ !!

How to know the details of CPU information

To know the information about the CPU,type


$ cat /proc/cpuinfo

Example is shown below:

How to show the details of hardware system components

To show the details of hardware system components,type


$ dmidecode -q


* Dmidecode means DMI table decoder. It contains a description of
system's hardware components and other useful information such
as serial number and BIOS version. To get the details of the
system components,you have to be a superuser. so type "sudo"
in-front of the command. Example is shown below

How to display PCI devices in your system

To get the details of PCI device, type


$ lspci -tv


example is shown below,

How to show USB devices in your system

To show USB devices,type


$ lsusb -tv


* lsusb is a utility to show the usb devices details ,example is
show below

How to plan a shutdown of the system

To plan a shutdown of the system, type


$ shutdown -h 16:30 &



To cancel a planned shutdown of the system,type


$ shutdown -c

How to view all files on the system with SUID configured

To view all files on the system with SUID configured, type


$ find / -perm -u+s

How to show the permits on files

To show permits on files, type

$ ls -lh

How to remove a service from all runlevels

To remove a service from all runlevels, type

$ update-rc.d -f remove <service_name>

How to open a PDF file

To open a PDF file,type

$ gnome-open abc.pdf

How to hide the user input in terminal

To hide user input in terminal, type

$ stty -echo

To turn on the user input, type

$ stty echo

How to know the ALSA (Advance Linux Sound Architecture) version

To get the ALSA version,type

$ cat /proc/asound/version

Example is shown below

How to know the size of a directory in your system

To know the size of a directory

$ du -sh directory_name


Example is show in figure below

How to know the memory usage in your system

To know the memory usage in your system, type

$ free -m

Example is shown in fig below

How to get your computer's Uptime

To get the Uptime of your computer,type

$ uptime

How to get the Kernel version in your system

To get the kernel version of your system,type

$ uname -r

How to give a temporary ip address in your system

For temporary network configuration you have to use 'ifconfig' command. This command configures the setting immediately and will b lost after a reboot.

$ sudo ifconfig eth0 192.168.1.2 netmask 255.255.255.0

Here we are configuring to eth0. After this command to check the present network interface you have to type the command

$ ifconfig eth0

Then will give the details of the eth0 ( example is show figure below)

How to find out the network interface available in your system

There is a command called 'lshw', it can identify all network interfaces in your system.

$ sudo lshw -class network

the above figure show all the information of bus information, product & vendor details,diver details and all other supported capabilities.

How to print the user id, group id, effective id and the supplementary groups

To print the user id (uid) and group id (gid), effective id (if different than the real id) and the supplementary groups.

    $ id username

`id' prints information about the given user, or the process running it
if no user is specified.By default, it prints the real user ID, real group ID, effective user ID if different from the real user ID, effective group ID if
different from the real group ID, and supplemental group IDs. In addition,
if SELinux is enabled and the `POSIXLY_CORRECT' environment variable
 is not set, then print `context=C', where C is the security context.

How to Backup and Restore your Ubuntu system using GUI application

To Backup and Restore your Ubuntu system, there is a GUI application called deja-dup .

How to print system info about a user

To print the system info about a user in ubuntu

    $ finger username