In /usr/bin/prelude-adduser line 7:
libdir=${prefix}/lib/x86_64-linux-gnu
^----^ SC2034: libdir appears unused. Verify use (or export if used externally).


In /usr/bin/prelude-adduser line 9:
datadir=${datarootdir}
^-----^ SC2034: datadir appears unused. Verify use (or export if used externally).


In /usr/bin/prelude-adduser line 16:
$bindir/prelude-admin $@
                      ^-- SC2068: Double quote array expansions to avoid re-splitting elements.

For more information:
  https://www.shellcheck.net/wiki/SC2068 -- Double quote array expansions to ...
  https://www.shellcheck.net/wiki/SC2034 -- datadir appears unused. Verify us...