mkdir — MaKe DIRectories.
Summary :
mkdir Create the DIRECTORY(ies) with the specified names, if they do not already exist.
Examples :
$ mkdir dir1 — Create a dir1, if dir1 is NOT an existing file or directory.
$ mkdir dir1 dir2 dir3 — Create 3 Directories.
$ mkdir -m 744 dir1 — Create a dir1 with specified permission mode.
$ mkdir -p dir1/dir2/dir3 — Make any missing parent directories for each argument. Suppose if dir1 or dir2 is NOT exist, then that dir will be created before creating the dir3.
$ mkdir -v dir1/dir2/dir3 — Print a message for each created dir.
Read : man mkdir