diff --git a/README.md b/README.md
index b837522..6482fa7 100644
--- a/README.md
+++ b/README.md
@@ -22,6 +22,7 @@ sootty "waveform.vcd" -o > image.svg
 
 with a Value Change Dump (VCD) or Extended VCD (EVCD) file to produce an svg waveform diagram. Optional arguments include:
 - `-b | --break FORMULA` Specify the formula for the points in time to be highlighted.
+- `--btable` Print the wire value table at breakpoints to `stdout` (`-b` is required).
 - `-e | --end FORMULA` Specify the end of the window.
 - `-h | --help` Show the help message and exit.
 - `-l | --length N` Specify the number of ticks in the window (mutually exclusive with `-e`).
diff --git a/sootty/__main__.py b/sootty/__main__.py
index 2365e46..2a6343e 100644
--- a/sootty/__main__.py
+++ b/sootty/__main__.py
@@ -40,6 +40,7 @@ def parse_args():
     parser.add_argument(
         "-b",
         "--break",
+        required='--btable' in sys.argv,
         type=str,
         metavar="FORMULA",
         dest="breakpoints",
@@ -48,7 +49,6 @@ def parse_args():
     parser.add_argument(
         '--btable',
         action="store_true",
-        required='-b' in sys.argv,
         help="print a breakpoint table to stdout",
     )
     parser.add_argument(