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Looking for the best way to easily validate the integrity of files/folder in OS X when copied from one location to another.

I've downloaded SuperSFV but it appears to be very slow. Also new to the concept of checksums, so looking for easiest/best practice to ensure that a copied directory or file(s) are identical on the destination as they were on the source.

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2 Answers

You can find the checksum of a file by typing in Terminal :

md5 myfile.ext

Example :

user1@machine ~ $ md5 myfile.ext 
MD5 (myfile.ext) = d7badf415dbd52c2c8b51e564baef8be


For all files in a directory :

for file in * ; do md5 $file; done
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how would I process an entire folder? –  Josh Newman Jul 28 '10 at 23:15
for file in * ; do md5 $file; done –  Kami Jul 28 '10 at 23:22
Thanks - now how do I (simply) run and compare it on the destination once copied? –  Josh Newman Jul 29 '10 at 1:51
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IIRC digest commands have been invoked slightly different in some versions of OSX. I'm talking like, Tiger as opposed to Snow Leopard, but I still know some people using Tiger. So, just in case 'md5' doesn't work by itself, try:

openssl md5 myfile.ext


And, FWIW, I have a bash alias in my .bashrc:

alias md5sum='openssl md5'

It just fits better with my Linux habits.

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"digests have changed in some versions of OSX" are you mad ? MD5 is a well defined hash algrorithm ! It will be full of nonsense to change it ! –  Kami Jul 30 '10 at 13:36
Ugh. Sorry. Totally not what I meant. What I mean is that digest commands changed. I seem to remember a day when a bare md5 command at the standard command line didn't work, and you had to do openssl md5 file.ext, or, openssl then md5 file.ext at the OpenSSL> prompt. –  VxJasonxV Aug 2 '10 at 23:47
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