diff --git a/bump.nim b/bump.nim
index 4c59377..a793661 100644
--- a/bump.nim
+++ b/bump.nim
@@ -397,6 +397,16 @@ proc bump*(minor = false; major = false; patch = true; release = false;
     debug "dry run and done"
     return
 
+  # if we're not on the master branch, let's just bail for now
+  let
+    branch = appearsToBeMasterBranch()
+  if branch.isNone:
+    crash "uh oh; i cannot tell if i'm on the master branch"
+  elif not branch.get:
+    crash "i'm afraid to modify any branch that isn't master"
+  else:
+    debug "good; this appears to be the master branch"
+
   # copy the new .nimble over the old one
   try:
     debug &"copying {temp} over", target
diff --git a/bump.nimble b/bump.nimble
index 8551b58..0655197 100644
--- a/bump.nimble
+++ b/bump.nimble
@@ -1,4 +1,4 @@
-version = "1.7.3"
+version = "1.7.4"
 author = "disruptek"
 description = "a tiny tool to bump nimble versions"
 license = "MIT"