diff --git a/USAGE.md b/USAGE.md
index 1a04382..7a0aa9e 100644
--- a/USAGE.md
+++ b/USAGE.md
@@ -20,7 +20,7 @@ does all this for you. See README.md for more details.
 .endm
 ```
 * `mips-linux-gnu-as -march=vr4300 -mabi=32 <dir>/target.s -o <dir>/target.o`
-* optional sanity checks:
+* optional sanity check:
   - `<dir>/compile.sh <dir>/base.c -o <dir>/base.o`
-  - `./diff.sh <dir>/target.o <dir>/base.o`
+  - `./permuter.py <dir> --debug`
 * `./permuter.py <dir>`
diff --git a/diff.sh b/diff.sh
deleted file mode 100755
index 20ae8bb..0000000
--- a/diff.sh
+++ /dev/null
@@ -1,17 +0,0 @@
-#!/bin/bash
-
-if [[ $# < 2 ]]; then
-	echo "Usage: $0 orig.o new.o [flags]"
-	exit 1
-fi
-
-if [ ! -f $1 -o ! -f $2 ]; then
-	echo Source files not readable
-	exit 1
-fi
-
-INPUT1="$1"
-INPUT2="$2"
-shift
-shift
-wdiff -n <(python3 ./src/objdump.py "$INPUT1" "$@") <(python3 ./src/objdump.py "$INPUT2" "$@") | colordiff | less -Ric