diff --git a/biopet.wdl b/biopet.wdl
index a1bf3d72bba36e9fae5749170b5fb6325ead32b5..8a23cf67cdfe58804a63727e56833e647dd50694 100644
--- a/biopet.wdl
+++ b/biopet.wdl
@@ -324,8 +324,8 @@ task ValidateAnnotation {
         set -e -o pipefail
         ${preCommand}
         ${toolCommand} \
-        ${"-r" + refRefflat} \
-        ${"-g" + gtfFile} \
+        ${"-r " + refRefflat} \
+        ${"-g " + gtfFile} \
         -R ${refFasta}
     }
 
@@ -355,7 +355,7 @@ task ValidateFastq {
     command {
         set -e -o pipefail
         ${preCommand}
-        ${toolCommand}\
+        ${toolCommand} \
         --fastq1 ${fastq1} \
         ${"--fastq2 " + fastq2}
     }
@@ -386,7 +386,7 @@ task ValidateVcf {
     command {
         set -e -o pipefail
         ${preCommand}
-        ${toolCommand}\
+        ${toolCommand} \
         -i ${vcfFile} \
         -R ${refFasta}
     }