From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Received: from metis.ext.pengutronix.de ([2001:67c:670:201:290:27ff:fe1d:cc33]) by merlin.infradead.org with esmtps (Exim 4.92.3 #3 (Red Hat Linux)) id 1kcVfG-0005H8-KL for barebox@lists.infradead.org; Tue, 10 Nov 2020 15:34:35 +0000 From: Ahmad Fatoum Date: Tue, 10 Nov 2020 16:34:29 +0100 Message-Id: <20201110153430.32123-1-a.fatoum@pengutronix.de> MIME-Version: 1.0 List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "barebox" Errors-To: barebox-bounces+u.kleine-koenig=pengutronix.de@lists.infradead.org Subject: [PATCH 1/2] doc: add note about characters like hyphens in variable names To: barebox@lists.infradead.org Cc: Ahmad Fatoum The mismatch between the allowed characters in shell variables and device parameters is a common pitfall, especially because device tree node names often have hyphens in them, which is disallowed by hush. While such variables can be read by the ${variable-example}, setting them is only possible with the setenv command. Reflect this in the documentation. Signed-off-by: Ahmad Fatoum --- Cc: Matthias Fend --- Documentation/user/driver-model.rst | 9 ++++++++- 1 file changed, 8 insertions(+), 1 deletion(-) diff --git a/Documentation/user/driver-model.rst b/Documentation/user/driver-model.rst index a0fd3e99b55b..c543d6d9c410 100644 --- a/Documentation/user/driver-model.rst +++ b/Documentation/user/driver-model.rst @@ -88,7 +88,14 @@ The parameters can be used as shell variables: .. code-block:: sh eth0.ipaddr=192.168.23.15 - echo "my current ip is: $eth0.ipaddr" + echo "my current ip is: ${eth0.ipaddr}" + +.. note:: + + Hush shell syntax for defining and setting variables is the same, so + some characters such as hyphens are not allowed on the left hand side + of a shell variable assignment. :ref:`command_setenv`, if enabled, + can still be used to write such a variable though. device variables may have a type, so assigning wrong values may fail: -- 2.28.0 _______________________________________________ barebox mailing list barebox@lists.infradead.org http://lists.infradead.org/mailman/listinfo/barebox