File::Copy(3perl) Perl Programmers Reference Guide File::Copy(3perl)
NAME
File::Copy - Copy files or filehandles
SYNOPSIS
use File::Copy;
copy("sourcefile", "destinationfile") or die "Copy failed: $!";
copy("Copy.pm", \*STDOUT);
move("/dev1/sourcefile", "/dev2/destinationfile");
use File::Copy "cp";
my $n = FileHandle->new("/a/file", "r");
cp($n, "x");
DESCRIPTION
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
The "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 with default options, while "copy" uses the default
permissions for the target file (which may depend on the process'
"umask", file ownership, inherited ACLs, etc.). That is, if the
destination file already exists, "cp" will leave its permissions
unchanged; otherwise the permissions are taken from the source file
and modified by the "umask". If an error occurs in setting
permissions, "cp" will return 0, regardless of whether the file was
successfully copied.
move
The "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
File::Copy also provides the "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[,$date_flag])
The first and second arguments may be strings, typeglobs, typeglob
references, or objects inheriting from IO::Handle; they are used in
all cases to obtain the filespec of the input and output files,
respectively. The name and type of the input file are used as
defaults for the output file, if necessary.
A new version of the output file is always created, which inherits
the structure and RMS attributes of the input file, except for owner
and protections (and possibly timestamps; see below). All data from
the input file is copied to the output file; if either of the first
two parameters to "rmscopy" is a file handle, its position is
unchanged. (Note that this means a file handle pointing to the
output file will be associated with an old version of that file
after "rmscopy" returns, not the newly created version.)
The third parameter is an integer flag, which tells "rmscopy" how to
handle timestamps. If it is < 0, none of the input file's
timestamps are propagated to the output file. If it is > 0, then it
is interpreted as a bitmask: if bit 0 (the LSB) is set, then
timestamps other than the revision date are propagated; if bit 1 is
set, the revision date is propagated. If the third parameter to
"rmscopy" is 0, then it behaves much like the DCL COPY command: if
the name or type of the output file was explicitly specified, then
no timestamps are propagated, but if they were taken implicitly from
the input filespec, then all timestamps other than the revision date
are propagated. If this parameter is not supplied, it defaults to
0.
"rmscopy" is VMS specific and cannot be exported; it must be
referenced by its full name, e.g.:
File::Copy::rmscopy($from, $to) or die $!;
Like "copy", "rmscopy" returns 1 on success. If an error occurs, it
sets $!, deletes the output file, and returns 0.
RETURN
All functions return 1 on success, 0 on failure. $! will be set if an
error was encountered.
NOTES
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).
AUTHOR
File::Copy was written by Aaron Sherman <ajs@ajs.com> in 1995, and
updated by Charles Bailey <bailey@newman.upenn.edu> in 1996.
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