s6-portable-utils
Software
skarnet.org
 The s6-chown program 
 s6-chown changes the owner and/or group of a file.
 Interface 
     s6-chown [ -U ] [ -u uid ] [ -g gid ] file
 -  s6-chown changes file's owner to (numeric) uid and group
to (numeric) gid. 
-  If uid isn't provided, the owner remains the same; if gid
isn't provided, the group remains the same. 
-  The -U option sets uid to the value of the UID
environment variable and gid to the value of the GID environment variable.
This makes s6-chown easily usable with
s6-envuidgid:
 s6-envuidgid account s6-chown -U file  changes file's uid and
gid to account's. 
 Posixness 
 s6-chown is not suitable as a Single Unix
chown
program.