add wrapper for single session support

diff --git a/.bin/tmux b/.bin/tmux
new file mode 100755 (executable)
index 0000000..d6ff4b2
--- /dev/null
+++ b/.bin/tmux
@@ -0,0 +1,49 @@
+#!/bin/sh
+set -eu
+
+LASTSESSIONIDFILE="${XDG_RUNTIME_DIR:-${TMPDIR:-/tmp}}/tmux-last-session-id"
+
+real_tmux() {
+  local exec; exec=exec
+  if [ -n "${_tmux_eval_only:-}" ]; then
+    exec=
+  fi
+  $exec $(which -a tmux | grep -v $HOME | head -1) "$@"
+}
+
+single_tmux_session() {
+  local id; id="$1"; shift
+  real_tmux new -t "$id" "$@"
+}
+
+tmux_session_exists() {
+  _tmux_eval_only=1 real_tmux has-session -t "$1"
+}
+
+if [ "${1:-}" = --connect-to-last ]; then
+  shift
+  if [ -f "$LASTSESSIONIDFILE" ]; then
+    UUID="$(cat $LASTSESSIONIDFILE)"
+    if tmux_session_exists $UUID; then
+      echo >&2 Attaching to existing session with ID $UUID…
+      single_tmux_session "$(cat $LASTSESSIONIDFILE)" "$@"
+    else
+      echo >&2 W: No tmux session with ID $UUID found, generating a new one…
+    fi
+  else
+    echo >&2 W: No tmux session ID stored, generating a new one…
+  fi
+
+elif [ -n "${1:-}" ]; then
+  real_tmux "$@"
+fi
+
+# only without argument create a new session with a random name/id to which we
+# can then attach
+
+UUID=$(uuidgen)
+echo "$UUID" > $LASTSESSIONIDFILE
+
+echo >&2 Starting a new session with ID $UUID…
+
+single_tmux_session $UUID "$@"