String Operators | Shell Script

Pre-Requisite: Conditional Statement in Shell Script There are many operators in Shell Script some of them are discussed based on string.

• Equal operator (=): This operator is used to check whether two strings are equal. Syntax:

Operands1 = Operand2

• Example: 

#!/bin/sh

str1="GeeksforGeeks";
str2="geeks";
if [ $str1 = $str2 ]
then
    echo "Both string are same";
else
    echo "Both string are not same";
fi

• Output:

Both string are not same

• Not Equal operator (!=): This operator is used when both operands are not equal. Syntax:

Operands1 != Operands2

• Example: 

#!/bin/sh

str1="GeeksforGeeks";
str2="geeks";
if [ $str1 != $str2 ]
then
    echo "Both string are not same";
else
    echo "Both string are same";
fi

• Output:

Both string are not same

• Less than (\<): It is a conditional operator and used to check operand1 is less than operand2. Syntax: Operand1 \< Operand2 Example: 

#!/bin/sh

str1="GeeksforGeeks";
str2="Geeks";
if [ $str1 \< $str2 ]
then
    echo "$str1 is less than $str2";
else
    echo "$str1 is not less than $str2";
fi

• Output:

GeeksforGeeks is not less than Geeks

• Greater than (\>): This operator is used to check the operand1 is greater than operand2. Syntax: Operand1 \> Operand2 Example: 

#!/bin/sh

str1="GeeksforGeeks";
str2="Geeks";
if [ $str1 \> $str2 ]
then
    echo "$str1 is greater than $str2";
else
    echo "$str1 is less than $str2";
fi

• Output:

GeeksforGeeks is greater than Geeks

• Check string length greater than 0: This operator is used to check the string is not empty. Syntax:

[ -n Operand ]

• Example: 

#!/bin/sh

str="GeeksforGeeks";
if [ -n $str ]
then
    echo "String is not empty";
else
    echo "String is empty";
fi

• Output:

String is not empty

• Check string length equal to 0: This operator is used to check the string is empty. Syntax:

[ -z Operand ]

• Example: 

#!/bin/sh

str="";
if [ -z $str ]
then
    echo "String is empty";
else
    echo "String is not empty";
fi

• Output:

String is empty