Basic Operators in Shell Scripting
Logical Operator or Boolean Operator:
&& -a {Logical AND}: Execute the command when both conditions are true
|| -o {Logical OR}: Any of one condition will work.
! ! {Not equal to}: Negates the result of the condition.
Note: If you will use “-a, -o, !” you need to use [ ] in condition while using for “&&, ||, !” you need to use [[ ]]. String Operator:
== {Equal to}: Check if two strings are equal.
!= {Not equal to}: Check if both strings are nt equal.
-z {zero length string}: Check if mentioned strings has zero length.
-n {non zero length string}: Check if string is non zero in length.Relational Operator:
-eq == {equal to}: Check if two strings are equal.
-ne != {Not equal to}: Check if two strings are not equal.
-lt < {less than}: Check if left is less than right.
-gt > {greater than}: Check if left is greater than right.
-le <= {less than equal to}: Check if left is less than equal to right.
-ge >= {greater than equal to}: Check if left is greater than equal to right.File Testing Operator:
-e filename {is it exists}
-f filename {is it a regular file}
-b filename {file is block special file or not}
-c filename {file is character special file or not}
-d filename {is it a directory}
-r filename {is it readable file}
-w filename {is it writable file}
-x filename {is it executable file}
-s filename {check size of file}Arithmetic Operators:
+ Addition
- Subtraction
* Multiplication
/ Division
% Modules
++ Increment Operator
-- Decrement OperatorNote: Below is the value which are vastly used in script.
0 - True,
1 - False