[bug#74878] [PATCH 2/2] scripts: substitute: Improve the help output.

[Richard Sent <richard@freakingpenguin.com>]

Clarify that arguments are read from standard input and that --query expects a
command.

* guix/scripts/substitute.scm (show-help): Reword.

Change-Id: Ifc197d5e10e43663f1e05039ce29086f6a21b943
---
 guix/scripts/substitute.scm | 11 +++++++----
 1 file changed, 7 insertions(+), 4 deletions(-)

diff --git a/guix/scripts/substitute.scm b/guix/scripts/substitute.scm
index 08ec172675..d5c2a84c33 100755
--- a/guix/scripts/substitute.scm
+++ b/guix/scripts/substitute.scm
@@ -244,13 +244,16 @@ (define-syntax with-networking
 
 (define (show-help)
   (display (G_ "Usage: guix substitute OPTION [ARGUMENT]...
-Internal tool to substitute a pre-built binary to a local build.\n"))
+Internal tool to substitute a pre-built binary to a local build.
+
+ARGUMENT is read from standard input, not from the command line.\n"))
   (display (G_ "
-      --query            report on the availability of substitutes for the
-                         store file names passed on the standard input"))
+      --query COMMAND STORE-FILE ...
+                         Run query COMMAND with STORE-FILE to report on
+                         the availability of substitutes"))
   (display (G_ "
       --substitute STORE-FILE DESTINATION
-                         download STORE-FILE and store it as a Nar in file
+                         download STORE-FILE and store it as a nar in file
                          DESTINATION"))
   (newline)
   (display (G_ "
-- 
2.46.0