What is the mkdir command in UNIX?

The mkdir command in UNIX allows users to create directories or folders as they are referred to in some operating systems. The mkdir command can create multiple directories at once and also set permissions when creating the directory. The user running the command must have appropriate permissions on the parent directory to create a directory or will receive a permission denied error.

How to create a directory

To create a directory in UNIX or Linux using the mkdir command pass the name of directory to the mkdir command.

mkdir mydirectory
ls
mydirectory

How to create multiple directories

To create multiple directories in UNIX or Linux using the mkdir command pass the names of directories to be created to the mkdir command. The names of directories should be separated by spaces.

mkdir foo bar baz
ls
foo bar baz

How to create parent directories

To create parent directories using the mkdir command pass the -p option. Suppose that the directory path foo/bar/baz is to be created. This can be created with mkdir as follows.

mkdir foo
cd foo
mkdir bar
cd bar
mkdir baz
tree foo
foo
└── bar
    └── baz

This may also be achieved in a single command with the -p flag.

mkdir -p foo/bar/baz
tree foo
foo
└── bar
    └── baz

Insufficient permissions when creating a directory

The mkdir command will return a permission denied error when trying to create a directory in a parent directory that the user does not have permissions for.

mkdir /etc/foo
mkdir: cannot create directory ‘/etc/foo’: Permission denied

In this instance to create a directory in this location the user will need sudo permissions or to contact a system administrator.

How to set permissions when creating a directory

To set permissions when creating a directory pass the -m option. This accepts a number value to set the file mode. If no options are passed to mdkir the directory will be created with read, write and execute permissions for the user (755). In the following example the directory is created to be world readable.

mkdir -m 777 foo
ls -la
total 12
drwxr-xr-x 3 george users 4096 Sep  9 20:59 .
drwxr-xr-x 8 george users 4096 Sep  9 20:47 ..
drwxrwxrwx 2 george users 4096 Sep  9 20:59 foo

Further reading

• mkdir man page
• The Linux mkdir command
• mkdir Wikipedia page