Question

I’m trying to write content to a file, /tmp/test.txt with AppleScript.

• If the file doesn’t exist, I want to create it.
• If it does exist, I want to replace the contents.

This is proving quite difficult because AppleScript has a different syntax for creating a new file versus writing to an existing file. I also thought about deleting a file if it already exists, and then creating it, but AppleScript will move things to the trash by default and so even that is rather complicated.

The data I am going to write to the file may have a lot of special characters in it, so I don’t really want to do something like do shell script "cat " + data + " > /tmp/txt.txt" because I am unaware of any escapeshellarg for AppleScript.

Below is what I have so far but I’m getting an error:

Can’t make file “Macintosh HD:private:tmp:test.txt” into type reference.

I would really like to abstract this by improving the helper function write_to_file that I got here so that it would take care of creating the file if it does not exist.

my write_to_file("hello", "/tmp/test.txt", false)

on write_to_file(this_data, target_file, append_data)
    try

        if not (exists POSIX file target_file) then
            make new document file at ("/tmp/" as POSIX file as alias) with properties {name:"test.txt", text:the_data}
        end if

        set the target_file to the target_file as POSIX file
        set the open_target_file to open for access file target_file with write permission
        if append_data is false then set eof of the open_target_file to 0
        write this_data to the open_target_file starting at eof
        close access the open_target_file
        return true
    on error e
        try
            display dialog e
            close access file target_file
        end try
        return false
    end try
end write_to_file

How can I create or replace a file using Applescript?

Answer 1

Try:

my write_to_file("hello", "/tmp/test.txt", true)

on write_to_file(this_data, target_file, append_data)
    try
        tell application "System Events" to exists file target_file
        if not the result then do shell script "> " & quoted form of target_file
        set the open_target_file to open for access target_file with write permission
        if append_data is false then set eof of the open_target_file to 0
        write this_data to the open_target_file starting at eof
        close access the open_target_file
        return true
    on error e
        try
            display dialog e
            close access target_file
        end try
        return false
    end try
end write_to_file