FIX: Strict syntax for kaust (#1077)

Co-authored-by: Husen M. Umer <husensofteng@users.noreply.github.com>

Author: maxulysse

conf/kaust.config

@@ -8,7 +8,7 @@ params {
 }
 
 // Load genome resources and assets hosted by the Bioinformatics team on IBEX cluster
-includeConfig 'https://raw.githubusercontent.com/bioinfo-kaust/references/refs/heads/main/configs/genomes.config'
+includeConfig (!System.getenv('NXF_OFFLINE') ? "https://raw.githubusercontent.com/bioinfo-kaust/references/refs/heads/main/configs/genomes.config" : "/dev/null")
 
 singularity {
     enabled = true
@@ -17,7 +17,7 @@ singularity {
     // Use existing images from the centralized library, if available
     libraryDir = "/biocorelab/BIX/resources/singularity/images/"
     // Download images that are missing from the library to user space
-    cacheDir = "/ibex/user/$USER/.singularity/nf_images/"
+    cacheDir = "/ibex/user/${System.getenv('USER')}/.singularity/nf_images/"
 }
 
 process {