MD5 command of mac md5 default output format is different from md5sum command.

touch md5test.txt
md5 md5test.txt > md5test.txt.md5
cat md5test.txt.md5

output is

MD5 (md5test.txt) = d41d8cd98f00b204e9800998ecf8427e

Of cource mac’s md5 command has option to output md5sum format.

md5 -r md5test.txt

But there are already exist md5 that output format is mac style. And you want to compare them on linux. First mac format convert to md5sum format.

cat md5test.txt.md5 | awk  '{print $4"  "$2};' | awk '{gsub(/[\(\)]/, ""); print $0}'

result is

d41d8cd98f00b204e9800998ecf8427e  md5test.txt