String = PEEK [ # Stream , ] Length

Since 3.15

Peeks from the stream Stream a number of bytes specified by the Length argument, keeping them available for the next READ instruction, and returns it as a string.

If Length is negative, then at most (- Length) bytes are read until the end of the stream.

If the stream is not specified, then the standard input is used.

The poke bytes are available to the next READ instruction, but are lost if you call PEEK again without calling READ before!

See also