From 26fbafb26837e3e22ca4d7dbafdcc1408f668be7 Mon Sep 17 00:00:00 2001
From: Tsukasa OI <research_trasio@irq.a4lg.com>
Date: Fri, 8 Sep 2023 06:41:29 +0000
Subject: [PATCH] Detect Docker robustly

"&> /dev/null" works as a redirection from stdout/stderr to /dev/null
in Bash but not in POSIX shell (considered as an asynchronous execution
and the result of the "command" command cannot be retrieved).

As a result, it always assumes that Docker always exists.

This commit makes the redirection robust and portable (makes it possible
to detect "no Docker" condition correctly).

Signed-off-by: Tsukasa OI <research_trasio@irq.a4lg.com>
---
 Makefile | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/Makefile b/Makefile
index ad48dfe..2e220f1 100644
--- a/Makefile
+++ b/Makefile
@@ -41,7 +41,7 @@ all: build
 
 build: 
 	@echo "Checking if Docker is available..."
-	@if command -v docker &> /dev/null ; then \
+	@if command -v docker >/dev/null 2>&1 ; then \
 		echo "Docker is available, building inside Docker container..."; \
 		$(MAKE) build-container; \
 	else \
@@ -62,4 +62,4 @@ build-no-container:
 clean:
 	@echo "Cleaning up generated files..."
 	rm -f $(PDF_RESULT)
-	@echo "Cleanup completed."
\ No newline at end of file
+	@echo "Cleanup completed."