fix: ensure that SCRIPT_DIR exists

scripts/tmux_cmd_path.sh

@@ -0,0 +1,18 @@
+#!/bin/bash
+
+# Written by michaellee8 <ckmichael8@gmail.com> in Nov 2020 for 
+# https://github.com/tmux-plugins/tpm/issues/189 to prevent problems caused by 
+# tmux version mismatch between client and server. This script is 
+# licensed in public domain.
+
+# Try to get the process ID of the running tmux server, 
+# would be empty if not found
+TMUX_SERVER_PID=$(ps -eo pid=,comm= | grep 'tmux: server' | awk '{ print $1; }')
+
+if [[ -n "$TMUX_SERVER_PID" ]]; then
+    TMUX_CMD_PATH=$(realpath "/proc/$TMUX_SERVER_PID/exe" 2> /dev/null || echo "tmux" | sed -z '$ s/\n$//')
+else
+    TMUX_CMD_PATH='tmux'
+fi
+
+export TMUX_CMD_PATH

sensible.tmux

@@ -1,12 +1,9 @@
 #!/usr/bin/env bash
 
 CURRENT_DIR="$( cd "$( dirname "${BASH_SOURCE[0]}" )" && pwd )"
+SCRIPTS_DIR="$CURRENT_DIR/scripts"
 
-# Try to find the executable path of the currently running 
-# tmux server, fallback to just "tmux" if not found or no 
-# procfs aviliable (non-linux).
-export TMUX_CMD_PATH=$(realpath "/proc/$(tmux display -p '#{pid}')/exe" 2> /dev/null || echo "tmux" | sed -z '$ s/\n$//')
-echo "tmux executable used: $TMUX_CMD_PATH"
+source "$SCRIPTS_DIR/tmux_cmd_path.sh"
 
 # used to match output from `tmux list-keys`
 KEY_BINDING_REGEX="bind-key[[:space:]]\+\(-r[[:space:]]\+\)\?\(-T prefix[[:space:]]\+\)\?"