tss script can measure aech command duration

bin/tss

@@ -1,9 +1,17 @@
 #!/usr/bin/env python3
 
-from sys import stdin, stdout
+from sys import stdin, stdout, argv
 from time import time
 
+detailed = '-d' in argv
 start = time()
+last = start
 for line in stdin:
-    stamp = time() - start
-    stdout.write(f"{stamp:0.6f} {line}")
+    now = time()
+    duration = now - start
+    diff = now - last
+    last = now
+    if detailed:
+        stdout.write(f"{duration:0.6f} [{diff:0.6f}] {line}")
+    else:
+        stdout.write(f"{duration:0.6f} {line}")