As it seem to come down to awk I checked what was installed:
nanopi@nanopi:~$ apt -s install awk
NOTE: This is only a simulation!
apt needs root privileges for real execution.
Keep also in mind that locking is deactivated,
so don't depend on the relevance to the real current situation!
Reading package lists... Done
Building dependency tree
Reading state information... Done
Package awk is a virtual package provided by:
original-awk:armhf 2012-12-20-6
mawk:armhf 1.3.3-17+b3
gawk:armhf 1:4.2.1+dfsg-1
original-awk 2012-12-20-6
mawk 1.3.3-17+b3
gawk 1:4.2.1+dfsg-1
You should explicitly select one to install.
nanopi@nanopi:~$ sudo apt-show-versions awk
awk not installed (not available)
nanopi@nanopi:~$ apt-show-versions mawk
mawk:arm64 1.3.3-17+b3 installed: No available version in archive
nanopi@nanopi:~$ apt-show-versions gawk
gawk not installed (not available)
running the awk explicite with mawk
nanopi@nanopi:~$ mawk 'NR==FNR{regexps[$0];next}{for (r in regexps)if($0 ~ r)print r}' <(echo "(\.|^)*\.services\.generalmagic\.com$") <(echo "me.services.generalmagic.com")
Killed
BUT installing gawk
nanopi@nanopi:~$ sudo apt install gawk
nanopi@nanopi:~$ gawk 'NR==FNR{regexps[$0];next}{for (r in regexps)if($0 ~ r)print r}' <(echo "(\.|^)*\.services\.generalmagic\.com$") <(echo "me.services.generalmagic.com")
(\.|^)*\.services\.generalmagic\.com$
nanopi@nanopi:~$ pihole -q gstatic
Match found in exact whitelist
fonts.gstatic.com
Match found in https://raw.githubusercontent.com/StevenBlack/hosts/master/hosts:
csi.gstatic.com
Match found in https://hosts-file.net/ad_servers.txt:
csi.gstatic.com
p2-aahhyknavsj2m-wtnlrzkba6lht33q-if-v6exp3-v4.metric.gstatic.com
p2-f6rp6piuxns4u-uzq4vp76bu3w2tso-if-v6exp3-v4.metric.gstatic.com
p2-n3zurhre4jjvk-can5rb2f2a4urcxh-if-v6exp3-v4.metric.gstatic.com
p4-ajvwyt5lpjazy-us7r2dzqcjsqh7pt-164149-i1-v6exp3-v4.metric.gstatic.com
p4-ajvwyt5lpjazy-us7r2dzqcjsqh7pt-164149-i2-v6exp3-ds.metric.gstatic.com
p4-ajvwyt5lpjazy-us7r2dzqcjsqh7pt-164149-s1-v6exp3-v4.metric.gstatic.com
p4-ajvwyt5lpjazy-us7r2dzqcjsqh7pt-if-v6exp3-v4.metric.gstatic.com
p5-lj5aujgj7jl7w-r2pmxqvndsgx2im2-931517-i1-v6exp3-v4.metric.gstatic.com
p5-lj5aujgj7jl7w-r2pmxqvndsgx2im2-931517-i2-v6exp3-ds.metric.gstatic.com
s6.netlogstatic.com
v6exp3-ds.metric.gstatic.com
v6exp3-v4.metric.gstatic.com
Match found in https://raw.githubusercontent.com/r-a-y/mobile-hosts/master/AdguardMobileAds.txt:
csi.gstatic.com
Match found in https://raw.githubusercontent.com/r-a-y/mobile-hosts/master/AdguardDNS.txt:
metric.gstatic.com
diagnose.igstatic.com
Match found in https://raw.githubusercontent.com/r-a-y/mobile-hosts/master/EasyPrivacy3rdParty.txt:
csi.gstatic.com
diagnose.igstatic.com
Match found in https://www.github.developerdan.com/hosts/lists/ads-and-tracking-extended.txt:
connectivitycheck.gstatic.comwf.cbarsrv.com
gstaticadssl.l.google.com
metric.gstatic.com
anycast.metric.gstatic.com
anycast-stb.metric.gstatic.com
anycast1.metric.gstatic.com
anycast1-stb.metric.gstatic.com
anycast2.metric.gstatic.com
anycast2-stb.metric.gstatic.com
ds.metric.gstatic.com
s-v6exp1-ds.metric.gstatic.com
s-v6exp1-v4.metric.gstatic.com
stbcast.metric.gstatic.com
stbcast-stb.metric.gstatic.com
stbcast2.metric.gstatic.com
stbcast2-stb.metric.gstatic.com
stbcast3.metric.gstatic.com
stbcast3-stb.metric.gstatic.com
stbcast4.metric.gstatic.com
stbcast4-stb.metric.gstatic.com
stbcast5.metric.gstatic.com
stbcast5-stb.metric.gstatic.com
test-ipv6-dot-com-v6exp3-v4.metric.gstatic.com
unicast.metric.gstatic.com
unicast-stb.metric.gstatic.com
unicast2.metric.gstatic.com
unicast2-stb.metric.gstatic.com
v4.metric.gstatic.com
v6exp3-ds.metric.gstatic.com
v6exp3-v4.metric.gstatic.com
NO ERRORS!
There must be a difference between mawk and gawk resulting in the error we've seen.
Is pihole checking for awk during installation? Maybe extend to gawk?