### exit codes measured WITHOUT a pipe (the earlier run piped through tail and read TAIL's code) ###
plain check                 exit=0
--read-data                 exit=1
--read-data-subset=1/1      exit=1
--read-data-subset=100%   exit=1
--read-data-subset=50%    exit=1

### and what each SAID ###
--- o1 ---
no errors were found
--- o2 ---
Pack ID does not match, want 288afd3e868dc6bd210e33bd6f821e9f088a5fd71a0464c23ce82eb8217bf0cc, got 4b6847bb5eece6c56e69d7381733827330a4eb799fc26a92287a181edc496d2b
Fatal: repository contains errors
--- o3 ---
Pack ID does not match, want 288afd3e868dc6bd210e33bd6f821e9f088a5fd71a0464c23ce82eb8217bf0cc, got 4b6847bb5eece6c56e69d7381733827330a4eb799fc26a92287a181edc496d2b
Fatal: repository contains errors
--- o4 ---
Pack ID does not match, want 288afd3e868dc6bd210e33bd6f821e9f088a5fd71a0464c23ce82eb8217bf0cc, got 4b6847bb5eece6c56e69d7381733827330a4eb799fc26a92287a181edc496d2b
Fatal: repository contains errors
--- o5 ---
Pack ID does not match, want 288afd3e868dc6bd210e33bd6f821e9f088a5fd71a0464c23ce82eb8217bf0cc, got 4b6847bb5eece6c56e69d7381733827330a4eb799fc26a92287a181edc496d2b
Fatal: repository contains errors