File::Copy - Copy files or filehandles
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.
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 (and created if need be). Trying to copy a file on top
of itself is a fatal error.
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 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
.
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
.
On Mac OS (Classic), syscopy
calls Mac::MoreFiles::FSpFileCopy
,
if available.
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).
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.
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.
On Mac OS (Classic), the path separator is ':', not '/', and the current directory is denoted as ':', not '.'. You should be careful about specifying relative pathnames. While a full path always begins with a volume name, a relative pathname should always begin with a ':'. If specifying a volume name only, a trailing ':' is required.
E.g.
- copy("file1", "tmp"); # creates the file 'tmp' in the current directory
- copy("file1", ":tmp:"); # creates :tmp:file1
- copy("file1", ":tmp"); # same as above
- copy("file1", "tmp"); # same as above, if 'tmp' is a directory (but don't do
- # that, since it may cause confusion, see example #1)
- copy("file1", "tmp:file1"); # error, since 'tmp:' is not a volume
- copy("file1", ":tmp:file1"); # ok, partial path
- copy("file1", "DataHD:"); # creates DataHD:file1
- move("MacintoshHD:fileA", "DataHD:fileB"); # moves (doesn't copy) files from one
- # volume to another
File::Copy was written by Aaron Sherman <ajs@ajs.com> in 1995, and updated by Charles Bailey <bailey@newman.upenn.edu> in 1996.