MacOS – How to delete a specific line of a .txt file in AppleScript

applescriptmacostext;

I have a .txt file saved on my computer. This is the location of the file:

/Users/Me/Desktop/My Documents/My Fruit Log.txt

I want my AppleScript-based Automator application to delete a specific line of the .txt file.

The contents of the .txt file looks like this:

So, if:

set lineNumberToErase to 8

The resulting .txt file should be:

Notice how not only the text on that line is removed, but the entire line is gone as well.

Bonus points if the solution includes some sort of mechanism to ensure that not more than 1 line is removed from the file. My fear when automating deletions like this is that the script somehow erases the entire file (based on me making a small mistake somewhere).

Best Answer

Here's a do shell script AppleScript command solution using sed to delete the target line of the target file, in-place.

set targetFile to "/Users/Me/Desktop/My Documents/My Fruit Log.txt"
set lineNumberToErase to 8

do shell script "sed -i '' -e '" & lineNumberToErase & "d' " & quoted form of targetFile

If you want a backup of the target file made, change the sed option -i '' to -i '.bak', e.g.:

do shell script "sed -i '.bak' -e '" & lineNumberToErase & "d' " & quoted form of targetFile

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Updated Answer:

The code below it what I'd use to replace the original code offered as there appears to be a bug in AppleScript when using the do shell script command in the manner originally presented that isn't present went the code, in a representative manner, is run in a bash script in Terminal.

Note that anytimeopen for access is used, it needs to be coded to trap any errors and try and close the file, which this attempts to do. That said it is not necessarily then only error handling I'd employ and all coding answer I present are done so as proof of concept and the onus to write code employing reasonable error handing is yours to fulfill.

As coded, this will create the target file if it doesn't exist while adding the text to add to it and if it does exist, places the text to add as the top line of the target file.

set targetFilePathname to (POSIX path of (path to desktop as string) & "My Fruit Log.txt")

--    # set theTextToWrite to "This text will be written at the top of the file." & "\n"    
set theTextToWrite to "This text will be written at the top of the file." & "\n"
set theOriginalText to ""
try
    set theOriginalText to (read targetFilePathname) as string
end try
--    # set theTextToWrite to theTextToWrite & "\n" & theOriginalText
set theTextToWrite to theTextToWrite & "\n" & theOriginalText
try
    set referenceNumber to open for access targetFilePathname with write permission
    write theTextToWrite to referenceNumber starting at 0
    close access referenceNumber
on error eStr number eNum
    display dialog eStr & " number " & eNum buttons {"OK"} default button 1 with title "File I/O Error..." with icon caution
    try
        close access referenceNumber
    end try
    return
end try

Best Answer

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