You don't have to close
FILEHANDLE if you are immediately going to do another
open() on it, because
open() will close it for
open().) However, an explicit close on an input file
resets the line counter ($.), while the implicit close done by
open() does not.
If the file handle came from a piped open close will additionally return
FALSE if one of the other system calls involved fails
or if the program exits with non-zero status. (If the only problem was that
the program exited non-zero $! will be set to 0.) Also, closing a pipe will
wait for the process executing on the pipe to complete, in case you want to
look at the output of the pipe afterwards. Closing a pipe explicitly also
puts the exit status value of the command into
open(OUTPUT, '|sort >foo') # pipe to sort or die "Can't start sort: $!"; ... # print stuff to output close OUTPUT # wait for sort to finish or warn $! ? "Error closing sort pipe: $!" : "Exit status $? from sort"; open(INPUT, 'foo') # get sort's results or die "Can't open 'foo' for input: $!";
FILEHANDLE may be an expression whose value gives the real filehandle name.