Reproduce: ``` cat << EOF >> /tmp/check.sh #!/bin/sh git log HEAD~..HEAD | cat # sleep 1 EOF chmod +x /tmp/check.sh git rebase -p -x /tmp/check.sh base ``` If the `base` is far away enough it fails with "fatal: Unable to create '.../.git/index.lock': File exists." at an arbitrary commit. Abort current rebase, uncomment 'sleep 1' and repeat rebase. Now it doesn't fail. Version: git version 2.20.1 uname --all Linux lian 4.18.0-15-generic #16-Ubuntu SMP Thu Feb 7 10:56:39 UTC 2019 x86_64 x86_64 x86_64 GNU/Linux -- All the best, Aleksey Midenkov @midenok
