usermod --gid regroups every file under an account's home, and accounts were made
with / as home: they now have /nonexistent, and an older account's home is moved
there (without its files) before its group changes. A sub-path asked for later that
holds data not in the group waits for the operator as the root would. The take act
gives the group to hardlinked files an account owns (the *arr apps' downloads) and
leaves root's; a file's setuid or setgid bit the regroup takes is never put back, so
no setgid file hands out the library's group; each is counted. An apply no longer
waits for a running take walk.
jschoubben
c7551162d6