diff --git a/singularity/workflows_base.def b/singularity/workflows_base.def
index a5af84f2962767b821b0a2844e9c876d250b257c..9327a885ebbcc435efe1abb858a199cecf7cd834 100644
--- a/singularity/workflows_base.def
+++ b/singularity/workflows_base.def
@@ -94,7 +94,8 @@ From:python:3.7-buster
 	rsync -azvP rsync://hgdownload.soe.ucsc.edu/genome/admin/exe/linux.x86_64/bedGraphToBigWig /usr/local/bin/.
 	prog="bedGraphToBigWig"
 	echo "# ${prog}" >> /usr/local/share/doc/program_versions.txt
-	eval "${prog}" 2>> /usr/local/share/doc/program_versions.txt
+	# `|| :` is to "ignore" error exit code from bedGraphToBigWig
+	eval "${prog}" 2>&1 | head -1 >> /usr/local/share/doc/program_versions.txt || :
 	# It is possible to test whether the R install is already OK
 	deb_source="deb http://cran.irsn.fr/bin/linux/debian buster-cran35/"
 	echo ${deb_source} >> /etc/apt/sources.list.d/cran.list