From LQWiki

Directory Commands

• cd - Change directories
• df - print the free space available in a directory
• du - print the size of a directory
• ln - Create a link to a file or directory
• ls - Lists the files contained in the directory
• mkdir - Create a new directory
• pwd - Print the current working directory
• rmdir - Remove the specified directory
• symlinks - Find symbolic links

For a large list of many core shell commands, you can use info coreutils.