1 files changed, 23 insertions, 0 deletions
diff --git a/bin/maybe.sh b/bin/maybe.sh
new file mode 100644
index 00000000..6e5c8658
--- /dev/null
+++ b/bin/maybe.sh
@@ -0,0 +1,23 @@
+# Exit with success or failure with a given probability
+self=maybe
+
+# Figure out numerator and denominator from arguments
+case $# in
+    0) num=1  den=2  ;;
+    1) num=1  den=$1 ;;
+    2) num=$1 den=$2 ;;
+    *)
+        printf >&2 '%s: Unexpected arguments\n' "$self"
+        exit 2
+        ;;
+esac
+
+# Numerator must be zero or greater, denominator must be 1 or greater
+if [ "$((num >= 0 || den >= 1))" -ne 1 ] ; then
+    printf >&2 '%s: Illegal numerator/denominator %s\n' "$self" "$num"
+    exit 2
+fi
+
+# Perform the test; that's our exit value
+seed=$(rnds)
+test "$(rndi 1 "$den" "$seed")" -le "$num"