expectMatch

#!/bin/bash

set -euo pipefail

args=()
replaceNewLinesWith=
while [ "$#" -gt 0 ]; do
  case "$1" in
  --replaceNewLinesWith)
    shift
    replaceNewLinesWith=$1
    ;;
  *)
    args+=("$1")
    ;;
  esac
  shift
done

set -- "${args[@]}"

if [ -n "$replaceNewLinesWith" ]; then
  content=$(tr $'\n' "$replaceNewLinesWith" </dev/stdin)
else
  content=$(cat /dev/stdin)
fi
if ! grep -q "$@" <<<"$content"; then
  echo "could not grep $1 from «$content»" >&2
  exit 1
fi