diff --git a/metrics/cpu.sh b/metrics/cpu.sh
index b6584b5..59c4615 100644
--- a/metrics/cpu.sh
+++ b/metrics/cpu.sh
@@ -1,7 +1,7 @@
 #!/bin/sh
 
 collect () {
-  echo $(ps aux | awk '{sum+=$3} END {printf "%.1f\n", sum}' | tail -n 1)
+  report $(ps aux | awk '{sum+=$3} END {printf "%.1f\n", sum}' | tail -n 1)
 }
 
 docs () {
diff --git a/metrics/disk_io.sh b/metrics/disk_io.sh
new file mode 100644
index 0000000..3c05a50
--- /dev/null
+++ b/metrics/disk_io.sh
@@ -0,0 +1,31 @@
+# #!/bin/sh
+
+# if [ -z $DISK_IO_MOUNTPOINT ]; then
+#   if is_osx; then
+#     DISK_IO_MOUNTPOINT="disk0"
+#   else
+#     DISK_IO_MOUNTPOINT="/dev/vda"
+#   fi
+# fi
+
+# if is_osx; then
+#   __disk_io_bgproc () {
+#     iostat -K -d -c 99999 -w $INTERVAL $DISK_IO_MOUNTPOINT | while read line; do
+#       echo $line | awk '{print $3}' > ./foobar
+#     done
+#   }
+# else
+#   __disk_io_bgproc () {
+#     echo $(iostat -y -d 1 $DISK_IO_MOUNTPOINT)
+#   }
+# fi
+
+# init () {
+#   mkfifo ./foobar
+#   #exec 3<> ./foobar
+#   __disk_io_bgproc > ./foobar &
+# }
+
+# collect () {
+#   cat ./foobar
+# }
\ No newline at end of file
diff --git a/metrics/disk_usage.sh b/metrics/disk_usage.sh
index ed95e59..a06c7aa 100644
--- a/metrics/disk_usage.sh
+++ b/metrics/disk_usage.sh
@@ -9,8 +9,8 @@ if [ -z $DISK_USAGE_MOUNTPOINT ]; then
 fi
 
 collect () {
-  echo $(df | awk -v disk_regexp="^$DISK_USAGE_MOUNTPOINT" \
-              '$0 ~ disk_regexp {printf "%.1f", $5}')
+  report $(df | awk -v disk_regexp="^$DISK_USAGE_MOUNTPOINT" \
+                  '$0 ~ disk_regexp {printf "%.1f", $5}')
 }
 
 docs () {
diff --git a/metrics/memory.sh b/metrics/memory.sh
index 8d67154..ba85739 100644
--- a/metrics/memory.sh
+++ b/metrics/memory.sh
@@ -1,22 +1,18 @@
 #!/bin/sh
 
 if is_osx; then
-
   declare -r __memory_os_memsize=$(sysctl -n hw.memsize)
 
   collect () {
-    echo $(vm_stat | awk -v total_memory=$__memory_os_memsize \
+    report $(vm_stat | awk -v total_memory=$__memory_os_memsize \
             'BEGIN {FS="   *"; pages=0}
              /Pages (free|inactive|speculative)/ {pages+=$2}
              END {printf "%.1f", 100 - (pages * 4096) / total_memory * 100.0}')
   }
-
 else
-
   collect () {
-    echo $(free | awk '/buffers\/cache/{printf "%.1f", 100 - $4 / ($3 + $4) * 100.0}')
+    report $(free | awk '/buffers\/cache/{printf "%.1f", 100 - $4 / ($3 + $4) * 100.0}')
   }
-
 fi
 
 docs () {
diff --git a/metrics/network_io.sh b/metrics/network_io.sh
new file mode 100644
index 0000000..59c7190
--- /dev/null
+++ b/metrics/network_io.sh
@@ -0,0 +1,41 @@
+#!/bin/sh
+
+if [ -z $NETWORK_IO_INTERFACE ]; then
+  if is_osx; then
+    NETWORK_IO_INTERFACE="en0"
+  else
+    NETWORK_IO_INTERFACE="eth0"
+  fi
+fi
+
+declare -r __network_io_divisor=$(($INTERVAL*1024))
+__network_io_sample=(0 0)
+
+__network_io_calc_kBps() {
+  echo $1 $2 | awk -v divisor=$__network_io_divisor \
+        '{printf "%.2f", ($1 - $2) / divisor}'
+}
+
+if is_osx; then
+  __network_io_collect () {
+    netstat -bI $NETWORK_IO_INTERFACE | \
+                    awk "/$NETWORK_IO_INTERFACE/"'{print $7" "$10; exit}'
+  }
+else
+  __network_io_collect () {
+    echo TODO
+  }
+fi
+
+collect () {
+  local sample=( $(__network_io_collect) )
+  if [ ${__network_io_sample[0]} -ne 0 ]; then
+    report "in" $(__network_io_calc_kBps ${sample[0]} ${__network_io_sample[0]})
+    report "out" $(__network_io_calc_kBps ${sample[1]} ${__network_io_sample[1]})
+  fi
+  __network_io_sample=( "${sample[@]}" )
+}
+
+docs () {
+  echo "Network traffic in kB/s."
+}
\ No newline at end of file
diff --git a/metrics/swap.sh b/metrics/swap.sh
index b2e7c8c..909ae74 100644
--- a/metrics/swap.sh
+++ b/metrics/swap.sh
@@ -1,17 +1,13 @@
 #!/bin/sh
 
 if is_osx; then
-
   collect () {
-    echo $(sysctl -n vm.swapusage | awk '{printf "%.1f", $6 / $3 * 100.0}')
+    report $(sysctl -n vm.swapusage | awk '{printf "%.1f", $6 / $3 * 100.0}')
   }
-
 else
-
   collect () {
-    echo $(free | awk '/Swap/{printf "%.1f", $3/$2 * 100.0}')
+    report $(free | awk '/Swap/{printf "%.1f", $3/$2 * 100.0}')
   }
-
 fi
 
 docs () {
diff --git a/sysmetricsd.sh b/sysmetricsd.sh
index a6ca9af..4ee847a 100755
--- a/sysmetricsd.sh
+++ b/sysmetricsd.sh
@@ -1,7 +1,7 @@
 #!/bin/sh
 
 # config
-INTERVAL=2
+INTERVAL=1
 REPORTER=stdout
 
 #init
@@ -63,9 +63,23 @@ while true; do
       continue
     fi
 
-    result=$(__m_${metric}_collect)
-    __r_${REPORTER}_report $metric $result
+    report () {
+      local result
+      if [ -z $2 ]; then
+        label=$metric
+        result="$1"
+      else
+        label="$metric.$1"
+        result="$2"
+      fi
+      __r_${REPORTER}_report $label $result
+    }
+
+    __m_${metric}_collect
   done
 
   sleep $INTERVAL
-done
\ No newline at end of file
+done
+
+# trap 'kill $(jobs -pr)' SIGINT SIGTERM EXIT
+# trap "trap - SIGTERM && kill -- -$$" SIGINT SIGTERM EXIT
\ No newline at end of file