Variable:

There are two types of variables namely:
i) Local Variable (shell variable)
ii) Environment Variable

 

SHELL VARIABLES:
Shell allows you to define and use variable.

 

If you want to define a variable a with numerical value 10.

You can do so by typing the following at the shell prompt:

user1@ wtutopc ~]$ a=10            
(there must not be any space before and after = sign)

user1@ wtutopc ~]$ echo $a        
(show the value of variable a, if you don’t precede a with $ sign, the command will just display the character a)

 

user1@wtutopc ~]$ b= “Hello, this is wali”                     

user1@wtutopc ~]$ echo $b

 

NOTE: See use of quotes in 13.7.2(inhibiting expansion with quotes)

[root@wtutopc ~]# mkdir –p wali/dir1
[root@wtutopc ~]# path=”/root/wali/dir1”
[root@wtutopc ~]# cd  $path
[root@wtutopc dir1]# touch  file{1,2,3}
[root@wtutopc dir1]# cd
[root@wtutopc ~]# ls  $path

Note: Shell variables are local to a single shell by default;
Whereas Environment variables are not limited to a single shell.