File::Copy(3p) Perl Programmers Reference Guide File::Copy(3p) #
File::Copy(3p) Perl Programmers Reference Guide File::Copy(3p)
NNAAMMEE #
File::Copy - Copy files or filehandles
SSYYNNOOPPSSIISS #
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");
DDEESSCCRRIIPPTTIIOONN #
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
_n_a_m_e 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.
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yyoouu uussee ffiillee nnaammeess wwhheenneevveerr ppoossssiibbllee.. 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 _e_x_a_c_t_l_y 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
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, mmoovvee(()) 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".
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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, _e_t_c_. 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[,$date_flag])
The first and second arguments may be strings, typeglobs, typeglob
references, or objects inheriting from IO::Handle; they are used in
all cases to obtain the _f_i_l_e_s_p_e_c of the input and output files,
respectively. The name and type of the input file are used as
defaults for the output file, if necessary.
A new version of the output file is always created, which inherits
the structure and RMS attributes of the input file, except for owner
and protections (and possibly timestamps; see below). All data from
the input file is copied to the output file; if either of the first
two parameters to "rmscopy" is a file handle, its position is
unchanged. (Note that this means a file handle pointing to the
output file will be associated with an old version of that file after
"rmscopy" returns, not the newly created version.)
The third parameter is an integer flag, which tells "rmscopy" how to
handle timestamps. If it is < 0, none of the input file's timestamps
are propagated to the output file. If it is > 0, then it is
interpreted as a bitmask: if bit 0 (the LSB) is set, then timestamps
other than the revision date are propagated; if bit 1 is set, the
revision date is propagated. If the third parameter to "rmscopy" is
0, then it behaves much like the DCL COPY command: if the name or
type of the output file was explicitly specified, then no timestamps
are propagated, but if they were taken implicitly from the input
filespec, then all timestamps other than the revision date are
propagated. If this parameter is not supplied, it defaults to 0.
"rmscopy" is VMS specific and cannot be exported; it must be
referenced by its full name, e.g.:
File::Copy::rmscopy($from, $to) or die $!;
Like "copy", "rmscopy" returns 1 on success. If an error occurs, it
sets $!, deletes the output file, and returns 0.
RREETTUURRNN #
All functions return 1 on success, 0 on failure. $! will be set if an
error was encountered.
NNOOTTEESS #
Before calling ccooppyy(()) or mmoovvee(()) on a filehandle, the caller should close
or fflluusshh(()) the file to avoid writes being lost. Note that this is the
case even for mmoovvee(()), because it may actually copy the file, depending on
the OS-specific implementation, and the underlying filesystem(s).
AAUUTTHHOORR #
File::Copy was written by Aaron Sherman _<_a_j_s_@_a_j_s_._c_o_m_> in 1995, and
updated by Charles Bailey _<_b_a_i_l_e_y_@_n_e_w_m_a_n_._u_p_e_n_n_._e_d_u_> in 1996.
perl v5.36.3 2023-02-15 File::Copy(3p)