diff --git a/scripts/usage_compressed b/scripts/usage_compressed
index ce672db3b..59e93e669 100644
--- a/scripts/usage_compressed
+++ b/scripts/usage_compressed
@@ -7,6 +7,7 @@ test -x "$loc/usage" || exit 1
 
 echo 'static const char packed_usage[] = '
 "$loc"/usage | bzip2 -9 | od -v -t x1 \
-| sed -e 's/^[^ ]*//' -e 's/ \(..\)/\\x\1/g' -e 's/^\(.*\)$/"\1"/'
+| $SED -e 's/^[^ ]*//' -e 's/ \(..\)/\\x\1/g' -e 's/^\(.*\)$/"\1"/' || exit 1
 echo ';'
-echo '#define SIZEOF_usage_messages' $((0 + `"$loc"/usage | wc -c `))
+sz=`"$loc"/usage | wc -c` || exit 1
+echo '#define SIZEOF_usage_messages' `expr 0 + $sz`