What does the message “rewrite … (90%)” after a Git commit mean? [duplicate]

Answer 1

Its a measure of the similarity index. The similarity index is the percentage of unchanged lines. git thinks your file is text.

Answer 2

I believe Martin is correct, that number is the similarity index. From the git-diff man pages:

The similarity index is the percentage of unchanged lines, and the dissimilarity index is the percentage of changed lines. It is a rounded down integer, followed by a percent sign. The similarity index value of 100% is thus reserved for two equal files, while 100% dissimilarity means that no line from the old file made it into the new one.

First time I saw the number I thought my binaries were changing dramatically!.

Answer 3

It is attempting to rewrite CRs and LFs into a consistent format. That is, it doesn't see your binary file as binary. To force git to do this properly put the following line in .gitattributes:

*.bin -crlf -diff -merge

From this page that means:

all files with a [.bin] extension will not have carriage return/line feed translations done, won't be diffed and merges will result in conflicts leaving the original file untouched.