diff --git a/contrib/devtools/fix-copyright-headers.py b/contrib/devtools/fix-copyright-headers.py
index b6414a551..31a81ae4f 100755
--- a/contrib/devtools/fix-copyright-headers.py
+++ b/contrib/devtools/fix-copyright-headers.py
@@ -16,7 +16,7 @@ import time
 import re
 
 year = time.gmtime()[0]
-CMD_GIT_DATE = 'git log --format=@%%at -1 %s | date +"%%Y" -u -f -'
+CMD_GIT_DATE = 'git log --format=%%ad --date=short -1 %s | cut -d"-" -f 1'
 CMD_REGEX= "perl -pi -e 's/(20\d\d)(?:-20\d\d)? The Bitcoin/$1-%s The Bitcoin/' %s"
 REGEX_CURRENT= re.compile("%s The Bitcoin" % year)
 CMD_LIST_FILES= "find %s | grep %s"