``for`` is a loop construct. It will perform the commands specified by ``COMMANDS`` multiple times. On each iteration, the local variable specified by ``VARNAME`` is assigned a new value from ``VALUES``. If ``VALUES`` is empty, ``COMMANDS`` will not be executed at all. The ``VARNAME`` is visible when the loop terminates and will contain the last value assigned to it. If ``VARNAME`` does not already exist it will be set in the local scope. For our purposes if the ``for`` block is inside a function there must be a local variable with the same name. If the ``for`` block is not nested inside a function then global and universal variables of the same name will be used if they exist.
The last value assigned to ``var`` when the loop terminated would not be available outside the loop. What ``echo $var`` would write depended on what it was set to before the loop was run. Likely nothing.
