diff --git a/shellbox.tcl b/shellbox.tcl
index 007440a..cbb5ab5 100755
--- a/shellbox.tcl
+++ b/shellbox.tcl
@@ -19,11 +19,11 @@
 #
 # The box intercepts the following commands:
 #    exit or quit disconnect from the box
-#    clients dives a list of all connected clients
+#    clients gives a list of all connected clients
 #    kill terminates the shell
 #
 
-set version {$Id: shellbox.tcl,v 1.2 2002/10/23 09:22:46 zimoch Exp $}
+set version {$Id: shellbox.tcl,v 1.3 2003/03/10 10:04:57 zimoch Exp $}
 
 proc createServer {port {paranoid 0}} {
     if [catch {
@@ -102,7 +102,11 @@ proc forwardInput {data} {
 proc outputHandler {channel} {
     set data [read $channel]
     if [eof $channel] {
-        global command
+        global command diedyoung
+        if $diedyoung {
+            forwardOutput "**** first run of '$command' died within first 10 seconds. I will quit. ****\n"
+            exit 4
+        }
         forwardOutput "**** '$command' died ****\n"
         startProgram
         return
@@ -127,18 +131,23 @@ proc getClientlist {} {
     return $result
 }
 
+set diedyoung 1
 proc startProgram {} {
-    global command pipe
+    global command pipe diedyoung
     catch {close $pipe}
+    after 10000 set diedyoung 0
     if [catch {
-        set pipe [open "|$command" RDWR]
+        set pipe [open |$command RDWR]
     } msg] {
         puts stderr $msg
         exit 3
     }
     fconfigure $pipe -blocking no -buffering line
     gets $pipe
-    if [eof $pipe] exit
+    if [eof $pipe] {
+        forwardOutput "**** '$command' died immediately. I will quit ****\n"
+        exit 5
+    }
     fileevent $pipe readable "outputHandler $pipe"
     forwardOutput "**** '$command' started ****\n"
 }
@@ -164,7 +173,7 @@ if {[lindex $argv 0] == "-paranoid"} {
 
 set port [lindex $argv 0]
 set command [lrange $argv 1 end]
-if {![string is integer $port] || [llength $command] == 0} {
+if {![regexp {^[0-9]+$} $port] || [llength $command] == 0} {
     puts stderr "usage: [file tail $argv0] \[-paranoid\] <port> <command> \[args\]"
     exit 1
 }