diff --git a/lib/typing/chc_solver.ml b/lib/typing/chc_solver.ml
index 2e44cd0..72de464 100644
--- a/lib/typing/chc_solver.ml
+++ b/lib/typing/chc_solver.ml
@@ -41,41 +41,14 @@ let call_template cmd timeout =
     let _, out, _ = Fn.run_command ~timeout:timeout (Array.concat [cmd; [|file|]]) in
     lsplit2_fst out ~on:'\n'
 
-let prepare_fptprove_script () =
-  let script_path = "/tmp/fptprove_launch_script.sh" in
-  let script = {|
-    cd $2
-    timeout=605 # +5 is dirty hack for setting timeout for each iteration to 600 sec
-    options='-p pcsp'
-    rand=$RANDOM
-    setsid /bin/bash -c "$2/script/para_aux.sh $timeout $2/_build/default/main.exe -c $2/config/solver/pcsat_dt.json $options $1 > /tmp/fptprove_output1$rand" &
-    pgid1=$!
-
-    trap "kill -TERM -$pgid1" EXIT
-
-    while :
-    do
-        alive1=$(ps -ef | grep " $pgid1 " | grep -v grep | awk '{ print $2 }')
-        if [ -z "$alive1" ]; then
-            cat /tmp/fptprove_output1$rand
-            break
-        fi
-        sleep 0.5
-    done
-  |} in
-  let oc = open_out script_path in
-  Printf.fprintf oc "%s" script;
-  close_out oc;
-  script_path
-
 let call_fptprove timeout file = 
   let open Hflmc2_util in
   let fptprove_path = 
     try Sys.getenv "fptprove" with
     | Not_found -> Filename.concat (Sys.getenv "HOME") "bitbucket.org/uhiro/fptprove"
   in
-  let launch_script_path = prepare_fptprove_script () in
-  let _, out, _ = Fn.run_command ~timeout:timeout (Array.concat [[|"bash"|]; [|launch_script_path|]; [|file|]; [|fptprove_path|]]) in
+  let launch_script_path = Script.prepare_fptprove_script () in
+  let _, out, _ = Fn.run_command ~timeout:timeout [|"bash"; launch_script_path; file; fptprove_path; string_of_int ((int_of_float timeout) + 5)|] in
   let l = String.split out ~on:',' in
   match List.nth l 1 with
     | Some(x) -> x, Some ""
diff --git a/lib/typing/script.ml b/lib/typing/script.ml
new file mode 100644
index 0000000..3134dea
--- /dev/null
+++ b/lib/typing/script.ml
@@ -0,0 +1,96 @@
+let prepare_fptprove_script () =
+  let save_string path buf =
+    let oc = open_out path in
+    Printf.fprintf oc "%s" buf;
+    close_out oc;
+    path
+  in
+  let sub_script = {|
+    is_mac () {
+      sw_vers > /dev/null 2>&1
+      return $?
+    }
+
+    if is_mac ; then
+          date='gdate'
+    else
+          date='date'
+    fi
+
+    # Note that timeout changes its process group, so timeout cannot recieve SIGINT from a terminal.
+    # Note also that when ocaml invokes z3, SIGINT terminates not the whole program but just z3.
+    function interruptible_timeout() {
+      timeout $@ &
+      pgid=$!
+      # NOTE: when a script executed from another script, the INT signal will not be passed
+      trap "kill -TERM -$pgid" EXIT
+      wait $pgid
+    }
+
+    function nanosec2sec() {
+      sed -E 's/(.{9})$/.\1/' <<< "$1" | sed -E 's/^0*(0|([1-9][0-9]*))\./\1./'
+    }
+
+    start_time=$($date +%s%N)
+    output=`interruptible_timeout $@`
+
+    exit_code=$?
+
+    if [ $exit_code = 124 ]; then
+      end_time=$($date +%s%N)
+      elapsed=$(nanosec2sec "0000000000$((end_time - start_time))")
+        echo "${@:$#:1},timeout,$elapsed"
+        exit
+    fi
+
+    if [ $exit_code != 0 ]; then
+      echo "ERROR"
+      echo $exit_code
+      exit
+    fi
+
+    echo "OK!!!"
+
+    IFS="," read result iterations <<< "$output"
+
+    end_time=$($date +%s%N)
+    elapsed=$(nanosec2sec "0000000000$((end_time - start_time))")
+
+    if      [ "$result" = "valid" ] ||
+            [ "$result" = "invalid" ] ||
+            [ "$result" = "sat" ] ||
+            [ "$result" = "unsat" ] ||
+            [ "$result" = "unknown" ] ||
+            [ "$result" = "infeasible" ] ||
+            [ "$result" = "YES" ] ||
+            [ "$result" = "NO" ] ||
+            [ "$result" = "MAYBE" ]; then
+
+            echo "${@:$#:1},$result,$elapsed,$iterations"
+    else
+            echo "${@:$#:1},abort,$elapsed,$iterations"
+    fi
+  |} in
+  let sub_script_path = "/tmp/fptprove_launch_script_para_aux.sh" in
+  ignore @@ save_string sub_script_path sub_script;
+  let script = {|
+    cd $2
+    timeout=$3
+    options='-p pcsp'
+    rand=$RANDOM
+    setsid /bin/bash -c "/bin/bash |} ^ sub_script_path ^ {| $timeout $2/_build/default/main.exe -c $2/config/solver/pcsat_dt.json $options $1 > /tmp/fptprove_output1$rand" &
+    pgid1=$!
+
+    trap "kill -TERM -$pgid1" EXIT
+
+    while :
+    do
+        alive1=$(ps -ef | grep " $pgid1 " | grep -v grep | awk '{ print $2 }')
+        if [ -z "$alive1" ]; then
+            cat /tmp/fptprove_output1$rand
+            break
+        fi
+        sleep 0.5
+    done
+  |} in
+  save_string "/tmp/fptprove_launch_script.sh" script