The -ne Operator in Bash

1. Compare Strings Using the Not Equal Operator -ne in Bash
2. Compare Numbers Using the Not Equal Operator -ne in Bash

If two potential values are not equal, the -ne operator is used in Bash programming to compare them. In Bash, the not equal function is represented by the -ne character.

The != operator is used to express inequality. The logical outcome of the operation not equal is True or False.

The not equal expression is frequently combined with if or elif expressions to test for equality and execute sentences. -ne only works when brackets surround it [[]].

[[Value1 -ne Value2]]

• Value1 is generally a bash variable compared to Value2, which is a number.
• -ne cannot be used with the string types; instead, it throws an exception in the terminal that says integer expression expected.
• != is used to compare strings.

Compare Strings Using the Not Equal Operator -ne in Bash

As mentioned, we will use != to compare the strings. Let’s look at an example.

#!/bin/bash
nameone="Bobby"
nametwo="Shera"
 if [[ $nameone != $nametwo ]]; then
    echo "Not Equal!"
else
    echo "Equal!"
fi

We declared two string variables, nameone with the value Bobby and nametwo with the value Shera, and compared them using !=.

Output:

Not Equal!

Compare Numbers Using the Not Equal Operator -ne in Bash

We will use -ne to compare numbers. We will declare two integer variables, numone with the value 8 and numtwo with the value 9 and compare them using -ne.

#!/bin/bash
numone=8
numtwo=9
 if [[ $numone -ne $numtwo ]]; then
    echo "Not Equal!"
else
    echo "Equal!"
fi

Output:

Not Equal!