close -- close a file, which has been opened before
close # filenum
The close-command closes an open file. You should issue this command as soon as you are done with reading from or writing to a file.
close -2 closes all open files.
all = -2
open "my.data" for reading as 1
input #1 a
This program opens the file "my.data", reads a number from it, prints this number and then closes all files.