This tab tabs to the next tab stop for both read and write. It is the same as the nTL with n omitted; it tabs to the next tab stop.
The rules and Restrictions for tabbing are:
Tabbing right beyond the end of an input logical record is an error.
Tabbing left beyond the beginning of an input logical record leaves the input pointer at the beginning of the record.
Nondestructive tabbing is implemented for both internal and external formatted I/O. Nondestructive tabbing means that tabbing left or right on output does not destroy previously written portions of a record.
Tabbing right on output causes unwritten portions of a record to be filled with blanks.
Tabbing left requires that the logical unit allows a seek. Therefore, it is not allowed in I/O to or from a terminal or pipe.
Likewise, nondestructive tabbing in either direction is possible only on a unit that can seek. Otherwise, tabbing right or spacing with the X edit specifier writes blanks on the output.
Tab stops are hard-coded every eight columns.