TAB INSERT  (CTRL/I or TAB)
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 Moves the cursor in one of two ways:

     1.  If the tab size has not been set with SET TAB or if the cursor is not at
         the beginning of the line, a tab character is inserted at the cursor
         position.
     2.  If the tab size has been set with SET TAB or if the cursor is at the
         beginning of the line, a number of tab characters and spaces are
         inserted to move the cursor to the column position that is equal to the
         SET TAB value times the indentation level count.