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Perlito5X::File::Copy

Section: User Contributed Perl Documentation (3)
Updated: 2024-12-05
Index

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";        $n = FileHandle->new("/a/file","r");        cp($n,"x");

DESCRIPTION

The File::Copy module provides two basic functions, "copy" and"move", which are useful for getting the contents of a file fromone place to another.

copy

The "copy" function takes twoparameters: a file to copy from and a file to copy to. Eitherargument may be a string, a FileHandle reference or a FileHandleglob. Obviously, if the first argument is a filehandle of somesort, it will be read from, and if it is a file name it willbe opened for reading. Likewise, the second argument will bewritten to. If the second argument does not exist but the parentdirectory does exist, then it will be created. Trying to copya 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 sourcefile 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 afilehandle as the source when the destination is a directory.

Note that passing infiles as handles instead of names may lead to loss of informationon some operating systems; it is recommended that you use filenames whenever possible. Files are opened in binary mode whereapplicable. To get a consistent behaviour when copying from afilehandle to a file, use "binmode" on the filehandle.

An optional third parameter can be used to specify the buffersize used for copying. This is the number of bytes from thefirst file, that will be held in memory at any given time, beforebeing written to the second file. The default buffer size dependsupon the file, but will generally be the whole file (up to 2MB), or1k 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. Thebehavior is nearly the same as well: as of version 2.15, "cp" willpreserve the source file's permission bits like the shell utilitycp(1) would do, while "copy" uses the default permissions for thetarget file (which may depend on the process' "umask", fileownership, inherited ACLs, etc.). If an error occurs in settingpermissions, "cp" will return 0, regardless of whether the file wassuccessfully copied.

move

The "move" function also takes two parameters: the current nameand the intended name of the file to be moved. If the destinationalready exists and is a directory, and the source is not adirectory, then the source file will be renamed into the directoryspecified by the destination.

If possible, move() will simply rename the file. Otherwise, it copiesthe file to the new location and deletes the original. If an error occursduring 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 thatyou may use the "cp" alias for "copy".

syscopy

File::Copy also provides the "syscopy" routine, which copies thefile specified in the first parameter to the file specified in thesecond parameter, preserving OS-specific attributes and filestructure. For Unix systems, this is equivalent to the simple"copy" routine, which doesn't preserve OS-specific attributes. ForVMS systems, this calls the "rmscopy" routine (see below). For OS/2systems, 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'' ofthe input file to a new output file, in order to preserve fileattributes, indexed file structure, etc. The buffer sizeparameter is ignored. If either argument to "copy" is ahandle to an opened file, then data is copied using Perloperators, and no effort is made to preserve file attributesor record structure.

The system copy routine may also be called directly under VMS and OS/2as "File::Copy::syscopy" (or under VMS as "File::Copy::rmscopy", whichis the routine that does the actual work for syscopy).

rmscopy($from,$to[,$date_flag])

The first and second arguments may be strings, typeglobs, typeglobreferences, or objects inheriting from IO::Handle;they are used in all cases to obtain thefilespec of the input and output files, respectively. Thename and type of the input file are used as defaults for theoutput file, if necessary.

A new version of the output file is always created, whichinherits 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 theoutput file; if either of the first two parameters to "rmscopy"is a file handle, its position is unchanged. (Note that thismeans a file handle pointing to the output file will beassociated 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'stimestamps are propagated to the output file. If it is > 0, thenit is interpreted as a bitmask: if bit 0 (the LSB) is set, thentimestamps other than the revision date are propagated; if bit 1is set, the revision date is propagated. If the third parameterto "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 implicitlyfrom the input filespec, then all timestamps other than therevision date are propagated. If this parameter is not supplied,it defaults to 0.

"rmscopy" is VMS specific and cannot be exported; it must bereferenced 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 shouldclose or flush() the file to avoid writes being lost. Note that thisis the case even for move(), because it may actually copy the file,depending on the OS-specific inplementation, and the underlyingfilesystem(s).

AUTHOR

File::Copy was written by Aaron Sherman <ajsAATTajs.com> in 1995,and updated by Charles Bailey <baileyAATTnewman.upenn.edu> in 1996.

This document was created byman2html,using the manual pages.