add multi gpu support, closes #1

scripts/gpu.sh

@@ -2,13 +2,17 @@
 
 print_gpu_usage() {
     function getGPUUsage() {
-        gpuUsage=$(nvidia-smi -q -d UTILIZATION | grep Gpu | awk '{print $3}')
+	    gpuUsage=($(nvidia-smi -q -d UTILIZATION | grep Gpu | awk '{print $3}'))
     }
     getGPUUsage
-    if [ -z "$GpuUsage" ]; then
-        echo "$gpuUsage%"
-    else
+    gpuUsage=("${gpuUsage[@]/%/%}")
+    
+    function join_by { local IFS="$1"; shift; echo "$*"; }
+    gpuUsage=`join_by " " ${gpuUsage[@]}`
+    if [ -z "$gpuUsage" ]; then
 	echo "-"
+    else
+	echo "$gpuUsage"
     fi
 }