diff --git a/makeself-header.sh b/makeself-header.sh
index b991a5a..8c5b229 100755
--- a/makeself-header.sh
+++ b/makeself-header.sh
@@ -24,14 +24,7 @@ scriptargs="$SCRIPTARGS"
 cleanup_script="${CLEANUP_SCRIPT}"
 licensetxt="$LICENSE"
 helpheader="${HELPHEADER}"
-preextract='
-EOF
-if test -n "${PREEXTRACT_FILE}"; then
-    sed -e "s/['\\]/\\\\&/g" "${PREEXTRACT_FILE}" >> "$archname"
-fi
-cat << EOF  >> "$archname"
-'
-preextract="\${preextract#?}"; preextract="\${preextract%?}"  # trim redundant newlines
+preextract="${PREEXTRACT_ENCODED}"
 targetdir="$archdirname"
 filesizes="$filesizes"
 totalsize="$totalsize"
@@ -326,8 +319,8 @@ MS_Preextract()
         fi
     fi
 
-    prescript=\`mktemp -t XXXXX -p "\$tmpdir"\`
-    echo "\$preextract" > "\$prescript"
+    prescript=\`mktemp "\$tmpdir/XXXXXX"\`
+    echo "\$preextract" | base64 -d > "\$prescript"
     chmod a+x "\$prescript"
 
     (cd "\$tmpdir"; eval "\"\$prescript\" \$scriptargs \"\\\$@\""); res=\$?
@@ -495,7 +488,7 @@ EOLSM
         echo "Pre-extraction script is not provided." >&2
         exit 1
     fi
-    echo "\$preextract"
+    echo "\$preextract" | base64 -d
     exit 0
     ;;
     --confirm)
diff --git a/makeself.sh b/makeself.sh
index f3d87d8..d80abcf 100755
--- a/makeself.sh
+++ b/makeself.sh
@@ -313,9 +313,10 @@ do
     shift 2 || { MS_Usage; exit 1; }
 	;;
     --preextract)
-    PREEXTRACT_FILE="$2"
+    preextract_file="$2"
     shift 2 || { MS_Usage; exit 1; }
-    test -r "$PREEXTRACT_FILE" || { echo "Unable to open pre-extraction script: $PREEXTRACT_FILE" >&2; exit 1; }
+    test -r "$preextract_file" || { echo "Unable to open pre-extraction script: $preextract_file" >&2; exit 1; }
+    PREEXTRACT_ENCODED=`base64 "$preextract_file"`
     ;;
     --cleanup)
     CLEANUP_SCRIPT="$2"