Run any statement/command in all k8s pods with name matching a regex within a given context (kubectl config view )

runInPods.sh

#!/bin/bash -e
# runInPods.sh
# @description run any statement in all k8s pods with name matching a regex within a given context (kubectl config view ).  
# @author Nestor Urquiza
# @date 20180929
#
# @example1 For my-project, in my-cluster, in pods named '*nodejs*', run the 'ps -ef | grep node' command
# ./runInPods.sh -c gke_my-project_us-east1-b_my-cluster -r nodejs -s "ps -ef | grep node"
#

# options
while [[ $# -gt 1 ]]; do
  key="$1"
  case $key in
    -c|--context)
      context="$2"
      shift
    ;;
    -r|-regex)
      regex="$2"
      shift
    ;;
    -s|--statement)
      statement="$2"
      shift
    ;;
    *)
      # unknown
    ;;
  esac
  shift
done

# functions
function fail() {
  echo $1
  echo $USAGE
  exit 1
}

# main
USAGE="Usage:  `basename $0` (-c, --context --- from 'kubectl config view') [-r, --regex --- defaults to all)] (-s, --statement --- any valid command)"

if [ "$context" == "" ]; then
  fail "Context is mandatory. Find available contexts by running 'kubectl config view'"
fi

if [ "$regex" == "" ]; then
  regex=.
fi

if [ "$statement" == "" ]; then
  fail "Statement is mandatory. Use any linux command you want to run in the matching pod(s)'"
fi

kubectl config use-context $context
command="cat <("
for line in $(kubectl get pods | \
    grep "$regex" | grep Running | awk '{print $1}'); do 
  command="kubectl exec -i $line -- $statement"
  echo "Running $statement in $line"
  eval "$command"
done