Mac OS X, Mac OS X Server, Mac Security, Ubuntu, Unix Create 10,000 Empty Directories for Testing July 13, 2015 The mkdir command is used to create directories. Sometimes, in testing, you need to have a lot of directories. So, you can use the following command to create 10,000 5 digit directories, named 00001 to 10000: mkdir $(printf '%05d\n' {1..10000})