osc52 based clipboard script

cb

#!/usr/bin/env bash
# cb  — clipboard copy / paste using ONLY OSC 52 escape sequences
#       Works in any terminal that supports OSC 52 (iTerm2, kitty,
#       wezterm, recent xterm, etc.).  No tmux handling, no xclip,
#       no pbcopy.

set -euo pipefail
TIMEOUT=2    # seconds to wait for terminal’s reply when pasting

###############################################################################
osc52_copy() {
    # read stdin, base-64-encode to one long line
    local payload
    payload=$(base64 | tr -d '\n')

    # ESC ] 52 ; c ; <payload> BEL
    printf '\e]52;c;%s\a' "$payload" > /dev/tty
}

osc52_paste() {
    local request=$'\e]52;c;?\a'  # ask for clipboard
    local reply b64 oldstty

    # turn off local echo so the control sequence itself is not shown
    oldstty=$(stty -g)
    stty -echo -icanon time 0 min 0

    printf '%s' "$request" > /dev/tty

    # read until BEL (0x07) or TIMEOUT
    if ! IFS= read -r -d $'\a' -t "$TIMEOUT" reply < /dev/tty; then
        stty "$oldstty"
        echo "cb: timed out – terminal didn't answer OSC 52 query" >&2
        return 1
    fi
    stty "$oldstty"

    # strip the leading “ESC ] 52 ; … ;”
    reply=${reply#*$'\e]52;'}   # drop up to second field
    reply=${reply#*;}           # drop up to third semicolon

    # some terminals insert newlines into long sequences; remove them
    b64=${reply//$'\n'/}

    base64 -d <<<"$b64"
}

###############################################################################
usage() {
cat <<'EOF'
cb – copy to / paste from the clipboard using OSC 52 only

  echo "text" | cb         copy
  cb < file                copy
  cb -p        or  cb      paste / print

Options
  -p, --print   paste
  -h, --help    this help text
EOF
}

###############################################################################
# argument parsing
mode=auto
while [[ $# -gt 0 ]]; do
    case $1 in
        -p|--print) mode=paste ;;
        -h|--help)  usage; exit 0 ;;
        *) echo "cb: unknown option $1"; usage; exit 1 ;;
    esac
    shift
done
[[ $mode == auto ]] && { [[ -t 0 ]] && mode=paste || mode=copy; }

if [[ $mode == copy ]]; then
    osc52_copy
else
    osc52_paste
fi