How to: Bash Check if Directory Exists

In Bash scripting, it is often necessary to check whether a directory exists or not before performing any operations on it. This is especially important when writing scripts that will be run on multiple systems, as the directory structure may differ from one system to another. In this article, we will explore how to check if a directory exists in Bash, and provide code examples to illustrate the concept.

Understanding the test Command

The test command is used to check whether a file or directory exists in Bash. It is also known as the [ command, as it is often used with square brackets. The test command returns a status code of 0 if the file or directory exists, and a status code of 1 if it does not exist. This status code can be used in conditional statements to determine what actions to take.

Checking if a Directory Exists

To check if a directory exists in Bash, we can use the test command with the -d option. The -d option checks whether a directory exists, and returns a status code of 0 if it does exist, and 1 if it does not exist. Here is an example:

if [ -d /path/to/directory ]; then
    echo "Directory exists"
else
    echo "Directory does not exist"
fi

In the example above, we check if the directory at /path/to/directory exists. If it does exist, we print “Directory exists”. If it does not exist, we print “Directory does not exist”.

Using the && Operator

Another way to check if a directory exists in Bash is to use the && operator. The && operator executes the command on the right-hand side only if the command on the left-hand side returns a status code of 0. Here is an example:

[ -d /path/to/directory ] && echo "Directory exists" || echo "Directory does not exist"

In the example above, we check if the directory at /path/to/directory exists. If it does exist, we print “Directory exists”. If it does not exist, we print “Directory does not exist”.

Using the if Statement

We can also use the if statement to check if a directory exists in Bash. Here is an example:

if test -d /path/to/directory; then
    echo "Directory exists"
else
    echo "Directory does not exist"
fi

In the example above, we use the test command with the -d option to check if the directory at /path/to/directory exists. If it does exist, we print “Directory exists”. If it does not exist, we print “Directory does not exist”.

Conclusion

In Bash scripting, it is important to check if a directory exists before performing any operations on it. This can prevent errors and ensure that the script works as intended. In this article, we explored how to check if a directory exists in Bash using the test command with the -d option, the && operator, and the if statement. By understanding these concepts, you can write Bash scripts that are more robust and reliable.