Folder action to find and replace text and change line feeds

Question

I want to use a folder action to find and replace text and change Mac carriage returns to DOS line feeds inside text files.
The text to be replaced is: "/Users/wim/Music/iTunes/iTunes Music/Music" (without the quotes)
This text has to be removed (i.e. replaced by an empty string)
The text occurs many times within each file.
The files are playlists exported from iTunes in the M3U format (which are text files). They contain Mac carriage returns. These need to be changed to DOS line feeds.
I have found the following two perl commands to achieve this:
To find and replace text: perl -pi -w -e 's/THIS/THAT/g;' *.txt
To change carriage returns to line feeds: perl -i -pe 's/\015/\015\012/g' mac-file
I know that it's possible to make a folder action with Automator that executes a shell script.
What I want to do is drop the exported playlists in M3U format in a folder so that the folder action will remove the right text and change the carriage returns.
My questions are:
Is it possible to make a folder action that executes command line commands instead of shell scripts?
What is the correct syntax for the two commands when used in a folder action shell script? Especially, how do I escape the slashes (/) in the string to be removed?
Thanks for your help

Answer 1

Ok, I've include an applescript to run a shell command. The applesript command quoted form makes a string that will end up as a single string on the bash command line.  Depending on what you want to do, you may need multiple string on the bash command lines.  I've included some information on folder actions.
It is easier to diagnose problems with debug information. I suggest adding log statements to your script to see what is going on.  Here is an example.
    Author: rccharles
    For testing, run in the Script Editor.
      1) Click on the Event Log tab to see the output from the log statement
      2) Click on Run
    For running shell commands see:
    http://developer.apple.com/mac/library/technotes/tn2002/tn2065.html
on run
    -- Write a message into the event log.
    log "  --- Starting on " & ((current date) as string) & " --- "
    --  debug lines
    set desktopPath to (path to desktop) as string
    log "desktopPath = " & desktopPath
    set unixDesktopPath to POSIX path of desktopPath
    log "unixDesktopPath = " & unixDesktopPath
    set quotedUnixDesktopPath to quoted form of unixDesktopPath
    log "quoted form is " & quotedUnixDesktopPath
    try
        set fromUnix to do shell script "ls -l  " & quotedUnixDesktopPath
        display dialog "ls -l of " & quotedUnixDesktopPath & return & fromUnix
    on error errMsg
        log "ls -l error..." & errMsg
    end try
end run
How to set up a folder action.
1) right click on folder. click on Enable folder actions
2) Place script in
/Library/Scripts/Folder Actions Scripts
3) right click on folder. click on attach folder action
pick your script.
Create a new folder on the desktop & try.
You can put multiple folder actions on a folder. There are other ways of doing this.
Here is my test script:
on adding folder items to this_folder after receiving dropped_items
    repeat with dropped_item_ref in dropped_items
       display dialog "dropped files is " & dropped_item_ref & " on folder " & this_folder
    end repeat
end adding folder items to
How to  make the text into an AppleScript program.
Start the AppleScript Editor
/Applications/AppleScript/Script Editor.app
In Snow Leopard it's at: /Applications/Utilities/AppleScript Editor
Copy the script text to the Applescript editor.
Note: The ¬ is typed as option+return.  ption+return is the Applescript line continuation characters.
You may need to retype these characters.
Save the text to a file as an script and do not check any of the boxes below.