Bash - check if file is socket

In this article, we would like to show you how to check if file is socket in Bash.

Practical example

In this example, we use -S operator with specified path to check if file under the path is socket inside if statement.

script.sh file:

#!/bin/bash

path="/path/to/socket"

if [ -S "$path" ]; then
    echo "The file is socket."
fi

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

Run in command line:

./script.sh

Output:

The file is socket.

Altermative notation

1. test based solution

#!/bin/bash

path="/path/to/socket"

if test -S "$path"; then
    echo "The file is socket."
fi

Note: [ ] notation is shorthand of test command.

2. [[ ]] based solution

#!/bin/bash

path="/path/to/socket"

if [[ -S "$path" ]]; then
    echo "The file is socket."
fi

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

See also

1. Bash - check if file is executable

2. Bash - check if file is writable

3. Bash - check if file is readable

4. Bash - check if file is not zero size