Comparing contents of two folders

Question

Is there a way to compare the files in two folders--a folder on my machine and a folder on a removable storage device such as a PC card--and output the names of the files that are missing from the folder on my machine?
My machine often drops files unexpectedly when I copy them from my PC card to hard drive and I want to be able to then find the 2 or 3 missing files (out of 500-800 images which I have copied) quickly.
Thanks.
Pedro Paramo

Answer 1

'Is there a way to compare the files in two folder ...' - Yes.
'... a folder on my machine and a folder on a removable storage device such as a PC card ...' - I have no idea what a PC card is (with exception to the former PCMCI card - renamed PC Card. Please do not explain). Perhaps you mean an external storage device - like a USB 'thumb' drive, etc.
'My machine often drops files unexpectedly when I copy them from my PC card to hard drive' - Welcome to MacOS X.
Sample source code:
property destFolder : ((((path to desktop folder from user domain) as string) & "Destination Folder:") as alias) -- Provide the appropriate full path to the destination folder.
property srcFolder : "Source Folder" -- Provide the name of the source Folder.
on run -- Exectued if user double clicks on applet. Display an appropriate message.
display dialog "Drag USB 'thumb' drive(s) onto this applet, for further processing." buttons {"OK"} default button 1 giving up after 5
eproperty destFolder : "Destination Folder2" -- Provide the appropriate full path to the destination folder.
property srcFolder : "Source Folder" -- Provide the name of the source Folder.
property destPath : ((((path to desktop folder from user domain) as string) & destFolder) as alias) -- Your full path to your 'destFolder' may vary. If so, edit this line accordingly.
on run -- Exectued if user double clicks on applet. Display an appropriate message.
display dialog "Drag USB 'thumb' drive(s) onto this applet, for further processing." buttons {"OK"} default button 1 giving up after 5
end run
on open (dItems) -- Executed if user drags an item or items onto the applet.
my process_Items(dItems) -- Process dragged on items.
end open
on process_Items(tItems)
tell application "Finder"
try -- Capture any AppleScript created error(s).
set destItems to displayed name of every file of destPath -- Names of files in 'destFolder'.
on error
set destItems to {} -- Set 'destItems' to empty list, if 'destPath' is empty.
end try
repeat with i in tItems
if ((kind of i) is "Volume") then -- Limit 'kind' of items to process.
set srcItems to (every file of (((i as string) & srcFolder) as alias)) -- Names of files in 'i's (an individual volume) 'srcFolder'.
repeat with j in srcItems -- Cycle through list of files in 'srcFolder'.
try -- Capture any AppleScript created error(s).
if (not (destItems contains (displayed name of j))) then duplicate j to destPath -- Duplicate files in 'srcFolder' not in 'destFolder'.
on error
if (destItems is {}) then duplicate j to destFolder -- Duplicate files in 'srcFolder' not in 'destFolder'.
end try
end repeat
end if
end repeat
end tell
end process_Items
Save the above code as an 'Application' (AppleScript applet).
Drag any volume or volumes onto the applet for processing.