The s6-dnsip4 program
s6-dnsip4 finds the IPv4 addresses associated to a domain name.
s6-dnsip4 [ -q ] [ -r ] [ -t timeout ] domain
- s6-dnsip4 makes an A query for the name domain. It
waits for the result and prints the obtained IPv4 addresses, one per line,
then exits 0.
- If the domain exists but no relevant field has been found, it exits 1.
- If the DNS answered but no answer is available, it prints a relevant
error message and exits 2.
- By default, s6-dnsip4 looks for DNS cache addresses in the
/etc/resolv.conf file. If the DNSCACHEIP environment variable is set
and contains a list of IP (v4 or v6) addresses, separated by commas,
semicolons, spaces, tabs, newlines or carriage returns, then this list
is used instead.
- -q : qualify. Qualifies domain before resolution,
according to suffixes found in /etc/resolv.conf. If the DNSQUALIFY
environment variable is set and contains a list of suffixes separated by spaces,
tabs, newlines or carriage returns, then this list is used instead. By
default, no qualification is used: if domain is not a FQDN, a dot
is just appended to it.
- -r : random. By default, the program does not sort the
result, but prints them in the order received from the DNS. With this
option, it performs a random permutation on the results before printing
- -t timeout : if the resolution takes more
than timeout milliseconds, then it exits 99 right away with an error
message. By default, timeout is 0, which means no timeout.