Syntax: Mark [0|1]
Abbreviation: M
sets the mark at the current position or cancels the previous mark. The mark can then be used to perform clip operations. The clip commands act on the characters lying between the mark and the cursor.
If you invoke Mark
with no arguments, it will toggle the mark. If you
specify 0 or 1, the mark will be canceled or set to the current position,
respectively. A capital ‘M’ appears on the status bar, if the mark is
active.
See Record, for the reason the mark is implemented as a flag.