How do you create a directory in Unix?

To create a directory in Unix, use the mkdir command. The basic syntax is mkdir directory_name. If you need to create nested directories that may not exist yet, use the -p flag: mkdir -p parent/child/grandchild. The -p option tells mkdir to create any missing parent directories and suppresses errors if the target already exists. You can also set permissions at creation time with the -m option, e.g., mkdir -m 755 newdir to give read, write, and execute permissions to the owner and read/execute to others. After creation, you can verify with ls -ld directory_name to see the permissions and ownership. These simple commands are fundamental for organizing files and preparing the filesystem for further operations.