August 1998
Intermediate to advanced
800 pages
39h 20m
English
You need to copy a file, but Perl has no built-in copy command.
Use the copy function from the standard File::Copy
module:
use File::Copy; copy($oldfile, $newfile);
You can do it by hand:
open(IN, "< $oldfile") or die "can't open $oldfile: $!";
open(OUT, "> $newfile") or die "can't open $newfile: $!";
$blksize = (stat IN)[11] || 16384; # preferred block size?
while ($len = sysread IN, $buf, $blksize) {
if (!defined $len) {
next if $! =~ /^Interrupted/; # ^Z and fg
die "System read error: $!\n";
}
$offset = 0;
while ($len) { # Handle partial writes.
defined($written = syswrite OUT, $buf, $len, $offset)
or die "System write error: $!\n";
$len -= $written;
$offset += $written;
};
}
close(IN);
close(OUT);Or you can call your system’s copy program:
system("cp $oldfile $newfile"); # unix
system("copy $oldfile $newfile"); # dos, vmsThe File::Copy module provides copy and
move functions. These are more convenient than
resorting to low-level I/O calls and more portable than calling
system. move works across
file-system boundaries; the standard Perl built-in
rename (usually) does not.
use File::Copy;
copy("datafile.dat", "datafile.bak")
or die "copy failed: $!";
move("datafile.dat", "datafile.new")
or die "move failed: $!";Because these functions return only a simple success status, you can’t easily tell which file prevented the copy or move from being done. Copying the files manually lets you pinpoint which files didn’t copy, but it fills your ...