1 files changed, 73 insertions, 0 deletions
diff --git a/bin/dice b/bin/dice
new file mode 100755
index 0000000..4a145d0
--- /dev/null
+++ b/bin/dice
@@ -0,0 +1,73 @@
+#!/bin/sh
+set -eu
+
+usage() {
+	cat <<-'EOF'
+		Usage:
+		  dice [SIZE]
+		  dice -h
+	EOF
+}
+
+help() {
+	cat <<-'EOF'
+
+		Options:
+		  -h, --help    show this message
+
+		  SIZE          the size of the dice (default: 6)
+
+
+		Roll a dice of SIZE.  Caveat: rolling a dice more than once in
+		the same second will give you the same number.
+
+
+		Examples:
+
+		  Roll a dice of size 6:
+
+		    $ dice
+		    3
+
+		  Roll a D20:
+
+		    $ dice 20
+		    15
+	EOF
+}
+
+
+for flag in "$@"; do
+	case "$flag" in
+		--)
+			break
+			;;
+		--help)
+			usage
+			help
+			exit
+			;;
+		*)
+			;;
+	esac
+done
+
+while getopts 'h' flag; do
+	case "$flag" in
+		h)
+			usage
+			help
+			exit
+			;;
+		*)
+			usage >&2
+			exit 2
+			;;
+	esac
+done
+shift $((OPTIND - 1))
+
+
+SIZE="${1:-6}"
+RAND="$(awk 'BEGIN { srand(); print int(rand()*32768) }' /dev/null)"
+echo $(((RAND % SIZE) + 1))