basedec.sh: Add the `-s' option

basedec.sh

@@ -1,6 +1,6 @@
 #!/bin/sh
 usage() {
-	printf 'usage: %s [-t type] [file ...]\n' "${0##*/}" >&2
+	printf 'usage: %s [-s] [-t type] [file ...]\n' "${0##*/}" >&2
 	exit 64
 }
 case "$(printf %s "${0##*/}" | tr A-Z a-z)" in
@@ -17,7 +17,8 @@ b32=ABCDEFGHIJKLMNOPQRSTUVWXYZ234567
 b32hex=0123456789ABCDEFGHIJKLMNOPQRSTUV
 b64=ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/
 b64safe=ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789-_
-while getopts t: opt; do
+strict=0
+while getopts t:s opt; do
 	case "$opt" in
 	t)	case "$(printf %s "$OPTARG" | tr A-Z a-z)" in
 		16)	type=16;;
@@ -29,6 +30,7 @@ while getopts t: opt; do
 		*)	usage;;
 		esac
 		;;
+	s)	strict=1;;
 	*)	usage;;
 	esac
 done
@@ -52,7 +54,7 @@ case "$type" in
 *)	usage;; # Unreachable
 esac
 cat -- "$@" | awk -vbits="$bits" -valphabet="$alphabet" \
-    -vinsensitive="$insensitive" '
+    -vinsensitive="$insensitive" -vstrict="$strict" '
 	function leftshift(a, b) {
 		return a * 2 ** b
 	}
@@ -81,6 +83,7 @@ cat -- "$@" | awk -vbits="$bits" -valphabet="$alphabet" \
 					t = mask(t, b)
 					count++
 				}
-			}
+			} else if (strict && $i != "=") 
+				exit 65
 		}
 	}'