Bash - check if string is not equal to

In this article, we would like to show you how to check if check if string is not equal to another string in Bash.

Practical example

In this example, we use == operator to check if string is not equal to another string inside the if statement.

script.sh file:

#!/bin/bash

string="abc"

if [ "$string" != "test" ]; then
    echo "The strings are not equal"
fi

Note: this approach should be used in POSIX shells where other solutions may not work.

Run in command line:

./script.sh

Output:

The strings are not equal

Altermative notation

1. test based solution

#!/bin/bash

string="abc"

if test "$string" != "test"; then
    echo "The strings are not equal"
fi

Note: [ ] notation is shorthand of test command.

2. [[ ]] based solution

#!/bin/bash

string="abc"

if [[ "$string" != "test" ]]; then
    echo "The strings are not equal"
fi

Note: [[ ]] notation is like extended test command, adding additional features (e.g. regular expressions).

See also

1. Bash - check if string is equal to

2. Bash - check if string is less than (ASCII alphabetical order)

3. Bash - check if string is greater than (ASCII alphabetical order)