Running Commands in All tmux Sessions, Windows and Panes

tmux-shell-cmd "whoami"
tmux-shell-cmd --kill ". ${ZDOTDIR}/.zprofile && . ${ZDOTDIR}/.zshrc"

# sz is short for "source zsh" and SZ is the same thing BUT LOUDER!
alias sz='. ${ZDOTDIR}/.zprofile && . ${ZDOTDIR}/.zshrc'
alias SZ='tmux-shell-cmd --kill "sz"'

#!/usr/bin/env bash
# Run a shell command in all open tmux sessions, windows and panes.

set -o pipefail
set -o nounset

AUTO_KILL="${AUTO_KILL:-}"
KILL=
ARGS=()

# Handle parsing arguments sent to this script. Other than the --kill arg, it's
# expected the rest are related to the command you're running.
for arg in "${@}"; do
  case "${arg}" in
  --kill)
    KILL=1
    ;;
  *)
    ARGS+=("${arg}")
    ;;
  esac
done

COMMAND="${ARGS[*]}"

# This covers a few ways to use the script.
if [[ -z "${COMMAND:-}" ]]; then
  cat <<EOF
Usage:
  tmux-shell-cmd whoami
  tmux-shell-cmd --kill "echo 'kill any process before running this command'"
  AUTO_KILL=1 tmux-shell-cmd --kill <same as above except it won't prompt you>
EOF
  exit 1
fi

# If we're killing processes let's certainly give ourselves a warning in case
# we need to save files or close something important. The kill will happen with
# a SIGTERM so it's graceful but still, this could have side effects.
#
# We support AUTO_KILL so you can call this script from another script and
# not be blocked by having to answer yes manually.
if [[ -n "${KILL}" && -z "${AUTO_KILL}" ]]; then
  printf "All processes running in any tmux shell session (nvim, etc.) will be killed, save you work! Are you sure? (y/n) "
  read -r yn

  if [[ "${yn}" != "y" ]]; then
    printf "\nAborting, your command was not run within any shell session.\n"
    exit
  fi
fi

# This is a neat feature provided by tmux which allows us to loop over all
# panes. The -a includes all sessions, you can use -s for only the current
# session if you wanted that behavior instead. -F is how the output will be
# formatted, these values are provided by tmux.
tmux list-panes -a -F "#{session_name}:#{window_index}.#{pane_index} #{pane_pid}" | while read -r pane pid; do
  # The running process will always be your shell (zsh, bash, etc.), in this
  # case if we have something like nvim or htop running there will be a child
  # process of that pid.
  child_pid=$(pgrep -P "${pid}")
  was_killed=

  # Here we only want to kill a child process like nvim, htop, etc..
  if [[ -n "${KILL}" && -n "${child_pid}" ]]; then
    # We're using pkill and kill so child processes get killed for processes
    # that spawn a parent which cannot be killed with a normal kill. pkill is
    # useful for processes like docker compose up.
    kill "${child_pid}"
    pkill -P "${child_pid}"
    was_killed=1
  fi

  # NOTE: You can add optional custom logic here if you wanted, such as only
  # doing something when a specific command is running. For example, you can
  # do `ps -p "${child_pid}" -o command=` which gets the full command for the
  # child pid (ie. nvim myfile). You can use `-o comm=` to get just the binary
  # instead (ie. nvim).

  # We have these extra conditions because we want to run the command when
  # either of these conditions are true:
  # - There's no children (ie. a regular shell session)
  # - There's a child process and it was killed
  #
  # Then we send the command into each pane, the C-m at the end sends in Enter
  # which invokes the command instead of just placing it into your shell.
  [[ -z "${child_pid}" || -n "${was_killed}" ]] && tmux send-keys -t "${pane}" "${COMMAND}" "C-m"
done