Now works supe well. a -y option might be needed

termscripts/posixfy.sh

@@ -13,8 +13,12 @@ else
         dash "$0" "$1"/*
     elif [ -f "$1" ]; then
         echo "$1"
-        sed -E 's|^#!/bin/sh$|#!/usr/bin/env sh|g' "$1" > "$1" 
-        sed 's|mksh|dash|g' "$1"> "$1" 
+        first="$(sed -E 's|^#!/bin/sh$|#!/usr/bin/env sh|g' "$1")"
+        second="$(echo "$first" | sed 's|mksh|dash|g')"
+        cat "$1"
+        echo "-----------------------------------------"
+        echo "$second"
+        dash $TSCRIPTS/yes-or-no.sh "Confirm?" && echo "$second" > "$1"
     else
         echo "Unexpected error" 1>&2
         exit 1