Accidently the UTMP was zeroed with cp /dev/null utmp command (usually
we clean up wtmp file this way). After that, several scripts had stopped
to work, cause they are pulling run level with who -r command. Is it any
way to rebuild utmp file to have boot information inside (who,uptime
etc..). I solved my problem by ftp-ing utmp from another server with the
same OS, but still need to know, what can I do in such case, if there is
only one server.