systemd journalctl is buggy, isn’t it?! config: x86_64-opensuse-13.2

• http://www.b.shuttle.de/hayek/mediawiki/w/index.php?title=Main_Page#systemd_and_the_journal
• my configuration: x86_64-opensuse-13.2

# this is the code suggested by Lennart Poettering,
# but it does not work for me
# (complains improperly about $XDG_RUNTIME_DIR) :
$ journalctl --since=yesterday -p err
# but this works:
$ journalctl -b -p err
# and this, too:
$ journalctl --since=yesterday