sed Crib Sheet

sed (stream editor) is a linux command that can manipulate files.  It is particularly useful for doing match and replace on a whole file. Below is the linux syntax

Change from 'something' to 'something else

sample.txt

hello out
there
how are
you today


Simple single line match
> sed -i s/hello/goodbye/ sample.txt
goodbye out
there
how are
you today


Multiline replace.  Match on 'out'.  N adds the next line to the 'match space' and then there is a normal substitution on the 'match space'.
> sed -i "/out/{N;s/there/fred/}" sample.txt
hello out
fred
how are
you today

Kubernetes / kubectl Crib Sheet

Get and Describe

Generally the get and describe can be used for 'deployments', 'nodes', 'pods', 'services', 'secrets' etc

// Get a list of pods
> kubectl get pods

// Interact with the pod by getting a shell
> kubectl exec -it <pod-nane> /bin/bash

// Get a list of services
> kubectl get services

// Describe a service to see how to connect to it
> kubectl describe service <service-name>

Contexts

// Allow kubectl to see multiple config files - this isn't really a merge in that the files stay separate
> export KUBECONFIG=config:config-other:config-different

// List the Contexts (* = current)
> kubectl config get-contexts

// View all the config details
> kubectl config view

// Use a particular contextsa
> kubectl config use-context <context-name>

Secrets

Create a secret

> kubectl create secret generic ssh-key-secret --from-file=id_rsa=~/.ssh/id_rsa --from-file=id_rsa.pub=~/.ssh/id_rsa.pub