Hello Mark, Thank you very much for all your help! I ended up with the following script: ----- property script_fname : "DocComp.sh" -- your "external script" name -- by Kino, 2006-05-20 property file_1 : "" property runtime : 0 property firsttime : "yes" property firstfile_passed : "no" property secondfile_passed : "no" property filetypes : {".txt", ".html", ".rtf", ".rtfd", ".doc", ".docx", ".wordml", ".odt", ".webarchive", ".xml"} on idle if runtime < (current date) - 5 * minutes then set file_1 to "" quit end if return 1 end idle on open (droppedItemsList) set my_path to POSIX path of (path to me) set shell_scpt to quoted form of (my_path & "Contents/Resources/" & script_fname) set runtime to current date if (number of droppedItemsList) ≥ 3 then display dialog "This droplet accepts two files." return quit else if (number of droppedItemsList) = 1 then if firsttime = "yes" then display dialog "Please drop another file..." set firsttime to "no" end if if file_1 = "" then set file_1 to first item of (droppedItemsList) set file_1 to POSIX path of file_1 return else set file_2 to first item of (droppedItemsList) set file_2 to POSIX path of file_2 end if else if (number of droppedItemsList) = 2 then set file_1 to first item of (droppedItemsList) set file_1 to POSIX path of file_1 set file_2 to second item of (droppedItemsList) set file_2 to POSIX path of file_2 end if if file_1 = file_2 then display dialog "You have chosen the same file. Quitting..." return quit end if repeat with i in filetypes if file_1 ends with i then set firstfile_passed to "yes" end if if file_2 ends with i then set secondfile_passed to "yes" end if end repeat set thename_1 to do shell script "basename " & quoted form of file_1 set thename_2 to do shell script "basename " & quoted form of file_2 if firstfile_passed = "no" then display dialog "The first file \"" & thename_1 & "\" is not of the supported types. Quitting..." return quit end if if secondfile_passed = "no" then display dialog "The second file \"" & thename_2 & "\" is not of the supported types. Quitting..." return quit end if display dialog "Comparing " & return & thename_1 & return & "with " & return & thename_2 try do shell script "/bin/sh " & shell_scpt & space & quoted form of file_1 & space & quoted form of file_2 --set res to the result on error errMsg display dialog "An error occurred: " & errMsg end try set file_1 to "" set file_2 to "" set firsttime to "yes" set firstfile_passed to "no" set secondfile_passed to "no" quit end open ------- The "DocComp.sh" compares two files (of different types) with Unix diff, and displays the result in a nice (readable) rtf file with TextEdit. I will upload the result in my web site, when my friend, Kino, will give me the permission. Thank you very much again! Best regard, Nobumi Iyanaga Tokyo, Japan