A few data points on GNU coreutils. 1. It has a fairly good test suite, that rewrites should leverage. That can be easily done by setting $PATH to prepend the

A few data points on GNU coreutils. 1. It has a fairly good test suite, that rewrites should leverage. That can be easily done by setting $PATH to prepend the dir of the new tools, and running `make check` 2. To give an indication of the size of coreutils: $ for r in gnulib coreutils; do (cd $r && git ls-files | tr '\n' '\0' | wc -l --files0-from=- | tail -n1); done 985050 total 243154 total