"--depth" option for checkout and update commands. Default value is "infinity".
"empty" includes only the immediate target of the operation, not any of its file or directory children.
"files" includes the immediate target of the operation and any of its immediate file children.
"immediates" includes the immediate target of the operation and any of its immediate file or directory children. The directory children will themselves be empty.
"infinity" includes the immediate target, its file and directory children, its children's children, and so on to full recursion.
"as-it-is" takes the working depth from the current working copy, allows for setting update depth manually using --set-depth option.
More information can be found
here.