The first argument to find() is either a hash reference describing the
operations to be performed for each file, or a code reference.
Here are the possible keys for the hash:
wanted
The value should be a code reference. This code reference is called
the wanted() function below.
bydepth
Reports the name of a directory only AFTER all its entries
have been reported. Entry point finddepth() is a shortcut for
specifying "{ bydepth =" 1 }> in the first argument of find().
preprocess
The value should be a code reference. This code reference is used to
preprocess a directory; it is called after readdir() but before the loop that
calls the wanted() function. It is called with a list of strings and is
expected to return a list of strings. The code can be used to sort the
strings alphabetically, numerically, or to filter out directory entries based
on their name alone.
postprocess
The value should be a code reference. It is invoked just before leaving the
current directory. It is called in void context with no arguments. The name
of the current directory is in $File::Find::dir. This hook is handy for
summarizing a directory, such as calculating its disk usage.
follow
Causes symbolic links to be followed. Since directory trees with symbolic
links (followed) may contain files more than once and may even have
cycles, a hash has to be built up with an entry for each file.
This might be expensive both in space and time for a large
directory tree. See follow_fast and follow_skip below.
If either follow or follow_fast is in effect:
*
It is guaranteed that an lstat has been called before the user's
wanted() function is called. This enables fast file checks involving _.
*
There is a variable $File::Find::fullname which holds the absolute
pathname of the file with all symbolic links resolved
follow_fast
This is similar to follow except that it may report some files more
than once. It does detect cycles, however. Since only symbolic links
have to be hashed, this is much cheaper both in space and time. If
processing a file more than once (by the user's wanted() function)
is worse than just taking time, the option follow should be used.
follow_skip
"follow_skip==1", which is the default, causes all files which are
neither directories nor symbolic links to be ignored if they are about
to be processed a second time. If a directory or a symbolic link
are about to be processed a second time, File::Find dies.
"follow_skip==0" causes File::Find to die if any file is about to be
processed a second time.
"follow_skip==2" causes File::Find to ignore any duplicate files and
dirctories but to proceed normally otherwise.
no_chdir
Does not "chdir()" to each directory as it recurses. The wanted()
function will need to be aware of this, of course. In this case,
$_ will be the same as $File::Find::name.
untaint
If find is used in taint-mode (-T command line switch or if EUID != UID
or if EGID != GID) then internally directory names have to be untainted
before they can be cd'ed to. Therefore they are checked against a regular
expression untaint_pattern. Note that all names passed to the
user's wanted() function are still tainted.
untaint_pattern
See above. This should be set using the "qr" quoting operator.
The default is set to "qr|^([-+@\w./]+)$|".
Note that the parantheses are vital.
untaint_skip
If set, directories (subtrees) which fail the untaint_pattern
are skipped. The default is to 'die' in such a case.
The wanted() function does whatever verifications you want.
$File::Find::dir contains the current directory name, and $_ the
current filename within that directory. $File::Find::name contains
the complete pathname to the file. You are chdir()'d to
$File::Find::dir when the function is called, unless "no_chdir"
was specified. When <follow> or <follow_fast> are in effect, there is
also a $File::Find::fullname. The function may set
$File::Find::prune to prune the tree unless "bydepth" was
specified. Unless "follow" or "follow_fast" is specified, for
compatibility reasons (find.pl, find2perl) there are in addition the
following globals available: $File::Find::topdir,
$File::Find::topdev, $File::Find::topino,
$File::Find::topmode and $File::Find::topnlink.
This library is useful for the "find2perl" tool, which when fed,
See also the script "pfind" on CPAN for a nice application of this
module.
CAVEAT
Be aware that the option to follow symbolic links can be dangerous.
Depending on the structure of the directory tree (including symbolic
links to directories) you might traverse a given (physical) directory
more than once (only if "follow_fast" is in effect).
Furthermore, deleting or changing files in a symbolically linked directory
might cause very unpleasant surprises, since you delete or change files
in an unknown directory.