diff --git a/lib/utils/loader.sh b/lib/utils/loader.sh
index 483e31e..afb190c 100644
--- a/lib/utils/loader.sh
+++ b/lib/utils/loader.sh
@@ -3,7 +3,8 @@
 load_reporter_with_prefix () {
   local prefix=$1
   local file=$2
-  # dash will error if this variable is defined as `local`
+  local content
+
   content=$(sed \
           -e 's/^[[:space:]]*\(init[ ]*()[ ]*{\)/'"$prefix"'\1/' \
           -e 's/^[[:space:]]*\(report[ ]*()[ ]*{\)/'"$prefix"'\1/' \
@@ -16,6 +17,7 @@ load_reporter_with_prefix () {
 load_metric_with_prefix () {
   local prefix=$1
   local file=$2
+  local content
 
   # dash will error if this variable is defined as `local`
   content=$(sed \
diff --git a/metrics/disk_io.sh b/metrics/disk_io.sh
index 0486c3f..09a015e 100644
--- a/metrics/disk_io.sh
+++ b/metrics/disk_io.sh
@@ -21,7 +21,7 @@ if is_osx; then
   }
 else
   __disk_io_bgproc () {
-    iostat -y -m -d 1 $DISK_IO_MOUNTPOINT | while read line; do
+    iostat -y -m -d $INTERVAL $DISK_IO_MOUNTPOINT | while read line; do
       echo $line | awk '/[0-9.]/{ print $3 }' > $__disk_io_fifo
     done
   }
diff --git a/metrics/network_io.sh b/metrics/network_io.sh
index 1cc6993..30aa0e5 100644
--- a/metrics/network_io.sh
+++ b/metrics/network_io.sh
@@ -28,7 +28,8 @@ __network_io_calc_kBps() {
 }
 
 collect () {
-  local sample=$(__network_io_collect)
+  local sample
+  sample=$(__network_io_collect)
   if [ ! -z "$__network_io_sample" ]; then
     report "in" $(__network_io_calc_kBps $(echo $sample | awk '{print $1}') \
                                 $(echo $__network_io_sample | awk '{print $1}'))