Sourceable script to add `-i` / `--in-place` option to `jq`

jq-i

#!/bin/bash
# Add in-place editing support to `jq`
# `source` it in your profile to wrap around `jq`, or run it directly
JQ="${JQ:-"$(command -v jq)"}"
function jq() {
  # Original command line, minus -i/--in-place, in its original order
  local passthrough=()
  local positionals=()
  local inplace=
  local help=
  local hasFromFile=
  local suppressRemainder=
  local arg
  local original=("${@}")
  while [[ $# -gt 0 ]]; do
    arg="${1}"
    shift
    case "${arg}" in
      -i|--in-place)
        inplace=true;;
      -h|--help)
        help=true;;
      # Options that consume the following two arguments
      --arg|--argjson|--slurpfile|--rawfile)
        passthrough+=("${arg}" "${1}" "${2}")
        shift 2 || break;;
      # Options that consume the following argument
      -f|--from-file)
        hasFromFile=true
        passthrough+=("${arg}" "${1}")
        shift || break;;
      --indent|-L)
        passthrough+=("${arg}" "${1}")
        shift || break;;
      # Everything after these is an argument for the filter, not a file
      --args|--jsonargs)
        suppressRemainder=true
        passthrough+=("${arg}");;
      -*)
        passthrough+=("${arg}");;
      *)
        passthrough+=("${arg}")
        if [[ -z "${suppressRemainder}" ]]; then
          positionals+=("${arg}")
        fi;;
    esac
  done

  # Inform the user of the new flag
  if [[ -n "${help}" ]]; then
    "${JQ}" --help | sed '/--null-input/a\  -i, --in-place            update the file in-place;' || true
    return
  fi

  # If inplace wasn't flagged, just run JQ as normal
  if [[ -z "${inplace}" ]]; then
    "${JQ}" "${original[@]}"
    return $?
  fi

  # With -f, every positional is a file; otherwise the first is the filter.
  local files=("${positionals[@]}")
  if [[ -z "${hasFromFile}" ]]; then
    files=("${positionals[@]:1}")
  fi

  if [[ ${#files[@]} -ne 1 ]]; then
    echo "--in-place requires exactly one input file" >&2
    return 1
  fi

  local file="${files[0]}"
  local tmp ret
  tmp="$(mktemp)"
  rm -f "${tmp}"
  cp -dP "${file}" "${tmp}"
  "${JQ}" "${passthrough[@]}" > "${tmp}"
  ret=$?
  if [[ "${ret}" == "0" ]]; then
    mv "${tmp}" "${file}"
  else
    echo "Error: jq failed; \`${file}\` not modified" >&2
    rm -f "${tmp}"
    return "${ret}"
  fi
}

if [[ "${BASH_SOURCE[0]}" == "${0}" ]]; then
  jq "${@}"
fi