diff --git a/workflow/rna-seq.nf b/workflow/rna-seq.nf
index 4be9f4fdafb208267e5a7e7f1934f5a2e3b18641..bcdcb8b63f0a2872ec98bdc43a4583153f804f18 100644
--- a/workflow/rna-seq.nf
+++ b/workflow/rna-seq.nf
@@ -877,7 +877,7 @@ process countData {
     echo -e "LOG: counted" >> ${repRID}.countData.log
     
     # extract assigned reads
-    assignedReads=grep -m 1 'Assigned' *.countData.summary | grep -oe '\([0-9.]*\)'
+    assignedReads=grep -m 1 'Assigned' *.countData.summary | grep -oe '\\([0-9.]*\\)'
     echo -e \${assignedReads} > assignedReads.csv
     echo -e "LOG: assigned reads: "\${assignedReads} >> ${repRID}.countData.log