zulhfreelancer

This PowerShell script will continuously prints the current time and pings an IP address.

It will run in a loop until you press Ctrl+C to stop it.

# Replace <IP> with target host IP address
try {
    while ($true) {
        $timestamp = Get-Date -Format 'yyyy-MM-dd HH:mm:ss'
 $pingResult = ping  -n 1

zulhfreelancer

k get pods -A -o json | jq -r '.items[] | select(.status.podIPs != null) | .metadata.namespace + " " + .metadata.name + " " + (.status.podIPs[] | .ip)' | grep -w '<pod_ip>'

zulhfreelancer

How to install mysql2 0.5.3 gem on Ruby 2.7.8 + Homebrew MySQL 8.0 environment

# this is installed via asdf
$ ruby -v
ruby 2.7.8p225 (2023-03-30 revision 1f4d455848) [x86_64-darwin24]

$ brew list --versions | grep mysql
mysql-client 9.0.1
[email protected] 8.0.39

zulhfreelancer

How to find a pod by UID?

Option #1

kubectl get pods -A -o json | jq -r '.items[] | select(.metadata.uid == "<UID>") | .metadata.name, .metadata.namespace'

Option #2

zulhfreelancer

How to run a temporary psql container in Kubernetes for testing/debugging?

$ k run psql-client --rm -i --tty --image jbergknoff/postgresql-client --command /bin/sh
/ # which psql
/usr/bin/psql

/ # psql --version
psql (PostgreSQL) 12.3

zulhfreelancer

How to sort htop by CPU or Memory?

Sort by CPU

htop -s PERCENT_CPU

Sort by Memory / RAM

zulhfreelancer

# Replace the THE_SECRET_NAME
k get pods -A -o json | jq -r '.items[] | select(.spec.imagePullSecrets!=null)  | select(.spec.imagePullSecrets[].name=="THE_SECRET_NAME") | {namespace: .metadata.namespace, name: .metadata.name}'

zulhfreelancer

kubectl get clusterissuers -o json | jq -r '.items[] | select(.spec.acme != null) | select(.spec.acme.solvers[0] | keys[0]=="dns01") | {name: .metadata.name, provider: (.spec.acme.solvers[0].dns01 | keys[0])}'

zulhfreelancer

How to displays a brief summary of all IPv4 addresses assigned to the network interfaces Linux system?

Command:

ip -4 -br a

Sample output:

zulhfreelancer

How to check which network interface will be used to route/send packets for specific IP address?

# Install `ip` tool
apt update -y
apt install iproute2 -y

# Check
ip r get 8.8.8.8 fibmatch