exit status 1 not 1234

nextflow/backmap.nf

@@ -318,7 +318,7 @@ if(bamAvailable){
   }// process nanoporeMapping
 } else { //fi: assemblyAvailable
   println "specify either --assembly or --bam-files"
-  exit 1234
+  exit 1
 }
 // Merging of Illumina mapped reads
 process mergeIlluminaBamFiles {