add build command readme for reproducible build

diff --git a/Makefile b/Makefile
index 080235e10269e5e251a2e8701e937caf0f6928f6..f0057baebe70c0d4e33ac74439fb17a95a9c01a7 100644 (file)
--- a/Makefile
+++ b/Makefile
@@ -116,4 +116,5 @@ $(BUILDDIR)/$(PACKAGENAME).deb: \
        $(PACKAGEDIR)/DEBIAN/control
 
        mkdir -p $(@D)
+       umask 0022
        cd build && dpkg-deb --build --root-owner-group $(PACKAGENAME)
\ No newline at end of file

diff --git a/readme.md b/readme.md
index 4b2b3b02029e356809b41a62e7e1da7cd094deeb..20d74ea532b4289b8716fec82e7139fea60b3e8b 100644 (file)
--- a/readme.md
+++ b/readme.md
@@ -9,6 +9,13 @@ it can scan many pages with cut page into multiple pdfs.
 - scantopdfgray - scan into gray pdf
 - scantopdfbw - scan into black and white pdf
 
+## Build
+
+```
+export SOURCE_DATE_EPOCH=$(git log --max-count=1 --pretty='%ct')
+make
+```
+
 ## Usage
 
 scan 5 pages into one pdf `test.pdf`