bin/bdl: Put a `Usage:' prefix on the usage text.

diff --git a/bin/bdl b/bin/bdl
index f5fcba5e042e0271b090acdc05449c04d2655a51..659f903dbbfd678321853638ce5f1372eba70b93 100755 (executable)
--- a/bin/bdl
+++ b/bin/bdl
@@ -11,5 +11,5 @@ S                      = /
 %:; $(V_CURL_$V)curl -fsL -o$@.new $A "$B$S$*" && mv $@.new $@
 
 ## Help summary.
-help:; @echo "bdl [-j NPROC] [A=ARGS] B=BASE [S=SEP] URL..."
+help:; @echo "Usage: bdl [-j NPROC] [A=ARGS] B=BASE [S=SEP] URL..."
 .PHONY: help