[jwilk]

git-sizer uses the -C option, which was added in git v1.8.5:

https://github.com/git/git/commit/44e1e4d67d5148c245db362cc4...

RHEL7 ships with git v1.8.3.1.

There might be other compatiblity issues, e.g.: https://github.com/github/git-sizer/issues/18

[deadbunny]

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