| File::Copy - Copy files or filehandles |
File::Copy - Copy files or filehandles
use File::Copy;
copy("sourcefile","destinationfile") or die "Copy failed: $!";
copy("Copy.pm",\*STDOUT);
move("/dev1/sourcefile","/dev2/destinationfile");
use File::Copy "cp";
$n = FileHandle->new("/a/file","r");
cp($n,"x");
The File::Copy module provides two basic functions, copy and
move, which are useful for getting the contents of a file from
one place to another.
copy function takes two
parameters: a file to copy from and a file to copy to. Either
argument may be a string, a FileHandle reference or a FileHandle
glob. Obviously, if the first argument is a filehandle of some
sort, it will be read from, and if it is a file name it will
be opened for reading. Likewise, the second argument will be
written to. If the second argument does not exist but the parent
directory does exist, then it will be created. Trying to copy
a file into a non-existent directory is an error.
Trying to copy a file on top of itself is also an error.
copy will not overwrite read-only files.
If the destination (second argument) already exists and is a directory, and the source (first argument) is not a filehandle, then the source file will be copied into the directory specified by the destination, using the same base name as the source file. It's a failure to have a filehandle as the source when the destination is a directory.
Note that passing in
files as handles instead of names may lead to loss of information
on some operating systems; it is recommended that you use file
names whenever possible. Files are opened in binary mode where
applicable. To get a consistent behaviour when copying from a
filehandle to a file, use binmode on the filehandle.
An optional third parameter can be used to specify the buffer size used for copying. This is the number of bytes from the first file, that will be held in memory at any given time, before being written to the second file. The default buffer size depends upon the file, but will generally be the whole file (up to 2MB), or 1k for filehandles that do not reference files (eg. sockets).
You may use the syntax use File::Copy "cp" to get at the cp
alias for this function. The syntax is exactly the same. The
behavior is nearly the same as well: as of version 2.15, cp will
preserve the source file's permission bits like the shell utility
cp(1) would do, while copy uses the default permissions for the
target file (which may depend on the process' umask, file
ownership, inherited ACLs, etc.). If an error occurs in setting
permissions, cp will return 0, regardless of whether the file was
successfully copied.
move function also takes two parameters: the current name
and the intended name of the file to be moved. If the destination
already exists and is a directory, and the source is not a
directory, then the source file will be renamed into the directory
specified by the destination.
If possible, move() will simply rename the file. Otherwise, it copies
the file to the new location and deletes the original. If an error occurs
during this copy-and-delete process, you may be left with a (possibly partial)
copy of the file under the destination name.
You may use the mv alias for this function in the same way that
you may use the cp alias for copy.
syscopy routine, which copies the
file specified in the first parameter to the file specified in the
second parameter, preserving OS-specific attributes and file
structure. For Unix systems, this is equivalent to the simple
copy routine, which doesn't preserve OS-specific attributes. For
VMS systems, this calls the rmscopy routine (see below). For OS/2
systems, this calls the syscopy XSUB directly. For Win32 systems,
this calls Win32::CopyFile.
Special behaviour if syscopy is defined (OS/2, VMS and Win32):
If both arguments to copy are not file handles,
then copy will perform a ``system copy'' of
the input file to a new output file, in order to preserve file
attributes, indexed file structure, etc. The buffer size
parameter is ignored. If either argument to copy is a
handle to an opened file, then data is copied using Perl
operators, and no effort is made to preserve file attributes
or record structure.
The system copy routine may also be called directly under VMS and OS/2
as File::Copy::syscopy (or under VMS as File::Copy::rmscopy, which
is the routine that does the actual work for syscopy).
rmscopy($from,$to[,$date_flag])
A new version of the output file is always created, which
inherits the structure and RMS attributes of the input file,
except for owner and protections (and possibly timestamps;
see below). All data from the input file is copied to the
output file; if either of the first two parameters to rmscopy
is a file handle, its position is unchanged. (Note that this
means a file handle pointing to the output file will be
associated with an old version of that file after rmscopy
returns, not the newly created version.)
The third parameter is an integer flag, which tells rmscopy
how to handle timestamps. If it is < 0, none of the input file's
timestamps are propagated to the output file. If it is > 0, then
it is interpreted as a bitmask: if bit 0 (the LSB) is set, then
timestamps other than the revision date are propagated; if bit 1
is set, the revision date is propagated. If the third parameter
to rmscopy is 0, then it behaves much like the DCL COPY command:
if the name or type of the output file was explicitly specified,
then no timestamps are propagated, but if they were taken implicitly
from the input filespec, then all timestamps other than the
revision date are propagated. If this parameter is not supplied,
it defaults to 0.
rmscopy is VMS specific and cannot be exported; it must be
referenced by its full name, e.g.:
File::Copy::rmscopy($from, $to) or die $!;
Like copy, rmscopy returns 1 on success. If an error occurs,
it sets $!, deletes the output file, and returns 0.
All functions return 1 on success, 0 on failure. $! will be set if an error was encountered.
Before calling copy() or move() on a filehandle, the caller should
close or flush() the file to avoid writes being lost. Note that this
is the case even for move(), because it may actually copy the file,
depending on the OS-specific implementation, and the underlying
filesystem(s).
File::Copy was written by Aaron Sherman <ajs@ajs.com> in 1995, and updated by Charles Bailey <bailey@newman.upenn.edu> in 1996.
| File::Copy - Copy files or filehandles |