syntax: regexp
^(386|68000|68020|alpha|amd64|arm|arm64|mips|power|power64|sparc|sparc64|spim)/(bin|lib|init|mbr|pbs|boot[^/]+|s?9[^/]+)(/|$)
^(acme|sys/src)/(.*/)?[0125678vqki]\..*$
^(acme|sys/src)/.*\.[ao]?[0125678vqki]?$
^(dev|fd|net.*|srv|shr|env|root|proc|boot|mnt|n|bin|usr|cfg|cron|mail|tmp)(/|$)
^acme/bin/(386|68000|68020|alpha|amd64|arm|arm64|mips|power|power64|sparc|sparc64|spim)(/|$)
^adm/(cache|keys|netkeys|secstore|users|whois|timezone/local)(/|$)
^lib/(ndb|audio|firmware)(/|$)
^lib/rfc/(drafts|index|rfc.*)(/|$)
^sys/doc/.*\.(html|ps|pdf|png|out)$
^sys/lib/(pkg|lp/log|man/lookman/index)(/|$)
^sys/lib/python/.*\.(pyo|pyc|exe)$
^sys/log(/|$)
^sys/man/(searchindex|[1-9]/INDEX.*)$
^sys/src/.*\.(bits|debug|output|tab\.[hc])$
^sys/src/pkg(/|$)