Some of the Common system command are as follow:

1. Date : to display date and time

2. Cal : to display the calendar

3. Cal 11 2006 : display the calendar of Month 11 and year 2006

4. Clear : To clear the screen

5. ls : to list directory contents

color identification

blue : Directories

White : Files

Green : Executable files

Red ; Zip files, rpm, tar file

Different switches used with “ls” command

ls –l or ll : used for long listing including file and directory permission

(-) : file

(d) : Directory

(l) : Symbolic link

ls –a : shows all hidden files and directory. Any file followed by (.) is hidden file

ls –al : show all hidden files and directory with long listing or whole description

ls –d : shows all the directory

6. pwd: Print working directory

7. who am I : display the information of current terminal

8. who : display all the terminal in a network

9. history : it shows all the command your have used.

By default history stores last 1000 command which u have run. If u want to change

# vi /etc/profile

HIST SIZE =10

Save and exit

# history –c ( to clear all the previous command reside in history)