Bash - check if string is not empty

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

Practical example

In this example, we use -n operator to check if string length is not zero inside the if statement.

script.sh file:

#!/bin/bash

string="example text..."

if [ -n "$string" ]; then
    echo "The string is not empty"
fi

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

Run in command line:

./script.sh

Output:

The string length is not empty

Altermative notation

1. test based solution

#!/bin/bash

string="example text..."

if test -n "$string"; then
    echo "The string is not empty"
fi

Note: [ ] notation is shorthand of test command.

2. [[ ]] based solution

#!/bin/bash

string="example text..."

if [[ -n "$string" ]]; then
    echo "The string is not empty"
fi

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

See also

1. Bash - check if string is empty