Month: December 2007

Get the external IP of your system – useful if you have a dynamic ip… curl -s checkip.dyndns.org|sed -e ‘s/.*Current…

du shows the ‘disk usage’ – the space taken up by the files and folders in the current directory. du…

free gives the Memory info (in kilobytes). free #Output total used free shared buffers cached Mem: 2075000 667508 1407492 0…

The last command shows a history of logins… last

Add a \n after every line in a file using the sed command… sed G

System info about a user. Try: finger root. An admin needs it all the time finger user_name #finger root Login:…

The command cmp is similar to diff: # cmp file1 file2 file1 file2 differ: byte 10, line 1

Find the IP address of all the active interfaces. ifconfig | egrep -o ‘^[a-z0-9]{1,12}|inet addr:[0-9.]+’

If you use the diff command, you will be able to see the difference between the files as shown below:…

Find where the command executable is located… whereis perl