qrcam2clip.sh

#!/bin/bash
set -euo pipefail

cleanup() {
  test -n "$tmpf" && rm -f "$tmpf"
}

main() {
  trap cleanup EXIT
  tmpf="$(mktemp --suffix .png)"
  while true; do
    ffmpeg -y -f v4l2 -video_size 1280x720 -i /dev/video0 -update 1 -frames:v 1 "$tmpf" &>/dev/null
    out=$(ZXingReader -format QRCode -bytes "$tmpf" || true)
    test -n "$out" && xclip -sel c <<<"$out" && echo Copied && exit
    sleep 1
  done
}

main "$@"