[bootlin/training-materials updates] master: Boot time: add instructions (2855d680)

[Michael Opdenacker]

Repository : https://github.com/bootlin/training-materials
On branch  : master
Link       : https://github.com/bootlin/training-materials/commit/2855d680e11424d3827475652e0ba4789d80f527

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commit 2855d680e11424d3827475652e0ba4789d80f527
Author: Michael Opdenacker <michael.opdenacker at bootlin.com>
Date:   Thu Oct 24 07:38:16 2019 +0200

    Boot time: add instructions
    
    Signed-off-by: Michael Opdenacker <michael.opdenacker at bootlin.com>


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2855d680e11424d3827475652e0ba4789d80f527
 labs/boot-time-init-scripts/boot-time-init-scripts.tex | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/labs/boot-time-init-scripts/boot-time-init-scripts.tex b/labs/boot-time-init-scripts/boot-time-init-scripts.tex
index 153a7ffe..7887d796 100644
--- a/labs/boot-time-init-scripts/boot-time-init-scripts.tex
+++ b/labs/boot-time-init-scripts/boot-time-init-scripts.tex
@@ -368,7 +368,12 @@ In Buildroot's configuration interface, find and set
 
 Run \code{make clean} and \code{make}.
 
-Again, write down the new size of the root filesystem tar archive.
+Run \code{tar tvf output/images/rootfs.tar} to find out directories
+which are now empty and therefore can now be removed. Add such directories to
+your post-fakeroot script and regenerate the filesystem again.
+This should save a few extra bytes.
+
+Once more, write down the new size of the root filesystem tar archive.
 You should observe substancial space reduction. Let's keep this option!
 
 \subsection{Testing}