diff --git a/user/bin/sh-tmux b/user/bin/sh-tmux
new file mode 100755
index 0000000..288e96b
--- /dev/null
+++ b/user/bin/sh-tmux
@@ -0,0 +1,41 @@
+#!/bin/sh
+# tmux wrapper script to attach to unattached sessions and auto number session
+
+new_session () {
+    n=1
+    sessions="$(tmux ls -F '#S' 2> /dev/null )"
+    while :; do
+        for session in $sessions; do
+            if [ "$n" = "$session" ]; then
+                n=$((n+1))
+                continue 2
+            fi
+        done
+        break
+    done
+    tmux new-session -s $n 2> /dev/null
+}
+attach_session () {
+    for session in $(tmux ls -F '#{?session_attached,,#S}' 2> /dev/null); do
+        if [ ! -z "$session" ]; then
+            tmux attach -t "${session}" 2> /dev/null
+            return
+        fi
+    done
+    new_session
+}
+
+if [ "$1" = "-d" ]; then
+    SH_TMUX_PID=$(tmux show-environment | sed -n 's/^SH_TMUX_PID=//p')
+    kill -USR1 $SH_TMUX_PID
+    tmux detach-client
+else
+    trap 'NOTMUX=y exec $SHELL' USR1
+    export SH_TMUX_PID=$$
+
+    if [ "$1" != "-n" ]; then
+        attach_session
+    else
+        new_session
+    fi
+fi