Use the TAB nokeypad command when the line mode SET TAB command is in
 effect.  The TAB command inserts the correct number of tabs and blanks
 to position the cursor to the current tab level.  When SET NOTAB is in
 effect, or when the cursor is not at the beginning of a line, this
 command inserts an HT character, thus positioning the cursor to the next
 tab stop.  Tab stops are every eight columns.

 Format: TAB