Plan 9 from Bell Labs’s /usr/web/sources/plan9/rc/bin/b:
#!/bin/rc if(! test -f /srv/dos) dossrv >/dev/null </dev/null >[2]/dev/null unmount /n/b:>[2]/dev/null mount -c /srv/dos /n/b: /dev/fd1disk unmount /n/b >[2]/dev/null mount -c /srv/dos /n/b /dev/fd1disk