[pm-h] File::Find and system

[Russell L. Harris]

Running Linux, I need to execute various system utilities (including
"dos2unix") on multiple files in multiple directories.  The file
structure is similar to the following:

    foo/jan/01.txt
    foo/jan/02.txt
    foo/jan/03.txt
    ...
    foo/feb/01.txt
    foo/feb/02.txt
    foo/feb/03.txt
    ...
    foo/dec/01.txt
    foo/dec/02.txt
    foo/dec/03.txt
    ...
    bar/jan/01.txt
    bar/jan/02.txt
    bar/jan/03.txt
    ...
    bar/feb/01.txt
    bar/feb/02.txt
    bar/feb/03.txt
    ...
    bar/dec/01.txt
    bar/dec/02.txt
    bar/dec/03.txt
    ...
    foobar/jan/01.txt
    foobar/jan/02.txt
    foobar/jan/03.txt
    ...
    foobar/feb/01.txt
    foobar/feb/02.txt
    foobar/feb/03.txt
    ...
    foobar/dec/01.txt
    foobar/dec/02.txt
    foobar/dec/03.txt
    ...

Regrettably, not all Linux utilities have a recursive option, and I do
not wish to take the time to re-write and debug functions which
already are available as a standard utilities.

A very tedious approach would be to "cd" to "foo/jan/" and run
"dos2unix *.txt", then "cd" to "foo/feb/" and run "dos2unix *.txt",
etc.

I know that a Perl script can automate the process.  I just discovered
the Perl "File::Find" module and the Perl "system" function, and now I
am perusing the O'Reilly Perl books, trying to understand how to
combine the two into a script.

Afterward, I need to do involved search-and-replace processing on
these files which cannot be handled with system utilities.  I
previously have used Perl scripts for similar tasks, but never on a
multi-level directory.

So, learning how to run system utilities with "File::Find" appears to
me to be the logical first step.

RLH