awk command not working with kubectl exec - awk

Question

From outside container:
$ kubectl exec -it ui-gateway-0 -- bash -c "ps -ef | grep entities_api_svc | head -1"
root 14 9 0 10:34 ? 00:00:02 /svc/bin/entities_api_svc
$ kubectl exec -it ui-gateway-0 -- bash -c "ps -ef | grep entities_api_svc | head -1 | awk '{print $2}'"
root 14 9 0 10:34 ? 00:00:02 /svc/bin/entities_api_svc
From inside container:
[root#ui-gateway-0 /]# ps -ef | grep entities_api_svc | head -1 | awk '{print $2}'
14

Answer 1

I find it easier to use single quotes on the sh/bash command argument so it is closer to what you would type in the shell:
kubectl exec -it ui-gateway-0 -- \
bash -c 'ps -ef | grep entities_api_svc | head -1 | awk "{print \$2}"'
This means the awk uses double quotes, which requires the shell variable marker $ to be escaped.
In the original command, the shell running kubectl was replacing $2 with a zero length string so awk would see only print, which prints the whole line
Multiple levels of nesting
Nested shell escaping gets very obscure very quickly and hard to debug:
$ printf '%q\n' 'echo "single nested $var" | awk "print $2"'
echo\ \"single\ nested\ \$var\"\ \|\ awk\ \"print\ \$2\"
$ printf '%q\n' "$(printf '%q\n' 'echo "double nested $var" | awk "print $2"')"
echo\\\ \\\"double\\\ nested\\\ \\\$var\\\"\\\ \\\|\\\ awk\\\ \\\"print\\\ \\\$2\\\"
If you add a file grep-entities.sh in container
#!/bin/bash
set -uex -o pipefail
ps -ef | grep entities_api_svc | head -1 | awk '{print $2}'
You then don't need to worry about escaping
pid=$(sshpass -p "password" ssh vm#10.10.0.1 kubectl exec ui-gateway-0 -- /grep-entities.sh)
Also pgrep does the scripts job for you
kubectl exec ui-gateway-0 -- pgrep entities_api_svc