From 0ece7ed9d40dd0e54994529d24e8ed4f7dbbeb0e Mon Sep 17 00:00:00 2001 From: Amen Belayneh Date: Sat, 12 Sep 2015 15:26:14 +0800 Subject: [PATCH] add a documentation note on backslash usage in shell form of RUN Signed-off-by: Amen Belayneh --- docs/reference/builder.md | 6 ++++++ 1 file changed, 6 insertions(+) diff --git a/docs/reference/builder.md b/docs/reference/builder.md index 195139758f..5ce217b220 100644 --- a/docs/reference/builder.md +++ b/docs/reference/builder.md @@ -311,6 +311,12 @@ commands using a base image that does not contain `/bin/sh`. > If you want shell processing then either use the *shell* form or execute > a shell directly, for example: `RUN [ "sh", "-c", "echo", "$HOME" ]`. +> **Note**: +> If you choose to use the *shell* form, any time you want to continue a single +> `RUN` instruction onto the next line, it has to be ended with a backslash `\`. +> For example, `RUN /bin/bash -c 'source $HOME/.bashrc ;\` then on the next +> line ` echo $HOME '`. + The cache for `RUN` instructions isn't invalidated automatically during the next build. The cache for an instruction like `RUN apt-get dist-upgrade -y` will be reused during the next build. The