Finds AWS EC2 instances by name mask.

aws-ec2-find.sh

#!/bin/bash

if ! aws --version 2> /dev/null ; then
  echo >&2 "command \`aws' is not found; maybe awscli is not installed"
  exit 1
fi

if ! jq --version 2> /dev/null ; then
  echo >&2 "command \`jq' is not found; maybe jq is not installed"
  exit 1
fi

usage() {
  cat >&2 <<__
Usage: aws-ec2-find.sh [PROFILE] NAME_MASK

Where
  - PROFILE is a profile name from ~/.aws (used by awscli).
    If it isn't specified, default section from ~/.aws is applied.

  - NAME_MASK is a wildcard for name of ec2 instance(s).
__
}

case $# in
  1)
    profile=
    name_mask="$1"
    ;;
  2)
    profile="$1"
    name_mask="$2"
    ;;
  *)
    usage
    exit 2
    ;;
esac

if [ -z "$name_mask" ] ; then
  usage
  exit 2
fi

aws_filter="name=tag:Name,values=$name_mask"

jq_filter='
.Reservations[].Instances[] |
  .PublicDnsName // "-",
  (
    (.Tags // []) |
      map(select(.Key=="Name"))
        [].Value // "-"
  )
'

dns_longest='ec2-123-123-123-123.compute-1.amazonaws.com'

output=`
  aws ${profile:+--profile "$profile"} \
    ec2 describe-instances --filters "$aws_filter"
`
result=$?

if [ $result -ne 0 ] ; then
  echo >&2 "$output"
  exit $result
fi

echo "$output" |
  jq "$jq_filter" |
    xargs -n2 printf "%${#dns_longest}s    %s\\n"