• NAME
• SUPPORTED PLATFORMS
• SYNOPSIS
• DESCRIPTION
• Context
• Controling Recursion
• SEE ALSO
• AUTHOR

NAME

File::Recurse - Recurse over files, performing some function.

SUPPORTED PLATFORMS

• Linux
• Solaris
• Windows

SYNOPSIS

        use File::Recurse;
        use File::Copy;

        recurse { print } "/tmp";
        recurse {copy($_,"elsewhere") if -f $_} "dir";
        recurse(\&func, "/");

DESCRIPTION

The File::Recurse module is designed for performing an operation on a tree of directories and files. The basic usage is simmilar to the find.pl library. Once one uses the File::Recurse module, you need only call the recurse function in order to perform recursive directory operations.

The function takes two parameters a function reference and a directory. The function referenced by the first parameter should expect to take one parameter: the full path to the file currently being operated on. This function is called once for every file and directory under the directory named by the second parameter.

For example:

        recurse(\&func, "/");

would start at the top level of the filesystem and call ``func'' for every file and directory found (not including ``/'').

Perl allows a second form of calling this function which can be useful for situations where you want to do something simple in the function. In these cases, you can define an anonymous function by using braces like so:

        recurse {print $_[0]} "/";

This would print every file and directory in the filesystem. However, as an added convenience you can access the pathname in the variable $_. So the above could be rewritten as:

        recurse { print } "/";

Context

There is an optional third parameter which can be any scalar value (including a reference). This value is ignored by recurse, but will be passed as the second parameter to the user-defined function. This can be useful for building library routines that use recurse, so that they do not have to pass state to the function as global variables.

Controling Recursion

If you want to control how recursion happens, you have several options. First, there are some global variables that affect the overall operation of the recurse routine:

$MAX_DEPTH

This variable controls how far down a tree of directories recurse will go before it assumes that something bad has happened. Default: 100.

$FOLLOW_SYMLINKS

This variable tells recurse if it should descend into directories that are symbolic links. Default: 0.

Normally, the return value of the function called is not used, but if it is -1 or -2, there is a special action taken.

If the function returns -1 and the current filename refers to a directory, recurse will not descend into that directory. This can be used to prune searches and focus only on those directories which should be followed.

If the function returns -2, the search is terminated, and recurse will return. This can be used to bail when a problem occurs, and you don't want to exit the program, or to end the search for some file once it is found.

SEE ALSO

the File::Tools manpage

AUTHOR

Written in 1996 by Aaron Sherman, ajs@ajs.com