How to count differences between two files on linux?

shell count diff
Zsolt Botykai picture Zsolt Botykai · Oct 14, 2009 · Viewed 64.8k times · Source

I need to work with large files and must find differences between two. And I don't need the different bits, but the number of differences.

To find the number of different rows I come up with 

diff --suppress-common-lines --speed-large-files -y File1 File2 | wc -l

And it works, but is there a better way to do it?

And how to count the exact number of differences (with standard tools like bash, diff, awk, sed some old version of perl)?

Answer

Josh picture Josh · Jan 12, 2012

If you want to count the number of lines that are different use this:

diff -U 0 file1 file2 | grep ^@ | wc -l

Doesn't John's answer double count the different lines?

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