diff --git a/debian/rules b/debian/rules
index e246262..32be7ba 100755
--- a/debian/rules
+++ b/debian/rules
@@ -2,8 +2,13 @@
 
 # this is so awful
 PAREN = )
-BEEGFS_VERSION = $(shell head -n1 debian/changelog | awk -F'[()]' '{print $2}')
-BEEGFS_MAJOR = $(shell head -n1 debian/changelog | awk -F'[()]' '{split($2,a,"."); print a[1]}')
+
+# Read the first line of debian/changelog just once
+CHANGELOG_LINE := $(shell head -n1 debian/changelog)
+
+# Extract versions
+BEEGFS_VERSION := $(shell echo "$(CHANGELOG_LINE)" | awk -F'[()]' '{print $$2}')
+BEEGFS_MAJOR   := $(shell echo "$(CHANGELOG_LINE)" | awk -F'[()]' '{split($$2,a,"."); print a[1]}')
 
 BEEGFS_NVFS=1
 DPKG_EXPORT_BUILDFLAGS = 1