SEEK

SEEK [#]fnbr, pos

Will position the read/write pointer in a file that has been opened for RANDOM access to the ‘pos’ byte.

The first byte in a file is numbered one so

SEEK #5,1

will position the read/write pointer to the start of the file.

See also:
CLOSE
EOF
INPUT#
INPUT$
LINE INPUT
OPEN
PRINT
WRITE