Is there some way to get a checksum for a file with ASObjC in the same fashion as the md5 utility? Right now I will use the answer to check JPG files for equality, but I’m primarily interested in the answer just for learning purposes. Thanks.
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If you a wanting to compare the equality of the fies, perhaps sha1 would be useful:
set mySha to (do shell script "echo ‘full/image/path’ | openssl sha1")
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Thanks Paul and ralphcr for the responses.
I looked at the documentation Paul linked and did a Google search. CryptoKit seems ideal but that’s only available with Swift. I did find the following comment in a post somewhere, but I don’t know if this could be implemented with ASObjC:
If you want to create a MD5 from a file with these methods, then you can do NSData *fileContents = [NSData dataWithContentsOfFile:@“”]; NSString *myHash = [fileContents md5]; And yes, this would pull the whole file into memory. If you find a solution that works with file streams, please post it as an answer.
I queried Google Gemini AI and got full Objective-C code that apparently will create an MD5 checksum for a file, but, even if feasible, converting it to ASObjC code is beyond my abilities.
For JPG images, exiftool will return md5 checksums, but I suspect speed would be an issue.
I did try sha1 with do shell script. This works well and is a good solution, although when working with thousands of files the do shell script command slows things somewhat. Anyways, this is the solution I will use for now.
Just checked, and instead of having openssl sha1 in the do shell AppleScript command, openssl md5 also works, and gives the same result as the md5 and md5sum utilities.
By the way, with the md5 -q version you only get the hash, no need to parse where the hash went. With the md5sum and OpenSSL option you need to do openssl md5 -r | awk '{print $1}', or md5sum | awk '{print $1}'.