diff --git a/lib/main.sh b/lib/main.sh
index 8171516..86c1543 100644
--- a/lib/main.sh
+++ b/lib/main.sh
@@ -73,17 +73,22 @@ main_collect () {
   }
 
   # collect metrics
-  while true; do
-    for metric in ${__METRICS[@]}; do
-      if ! is_function __m_${metric}_collect; then
-        continue
-      fi
+  for metric in ${__METRICS[@]}; do
+    if ! is_function __m_${metric}_collect; then
+      continue
+    fi
 
+    fork () {
       __m_${metric}_collect
-    done
-
-    sleep $INTERVAL
+      sleep $INTERVAL
+      fork
+    }
+    fork &
+    unset -f fork
   done
+
+  # run forever
+  tail -f /dev/null # `sleep infinity` is not portable
 }
 
 main_terminate () {
diff --git a/metrics/disk_io.sh b/metrics/disk_io.sh
index b5d3215..809e13f 100644
--- a/metrics/disk_io.sh
+++ b/metrics/disk_io.sh
@@ -26,7 +26,7 @@ else
 fi
 
 collect () {
-  report $(cat < $__disk_io_fifo)
+  report $(cat $__disk_io_fifo)
 }
 
 terminate () {
diff --git a/metrics/swap.sh b/metrics/swap.sh
index 2c14c66..640a885 100644
--- a/metrics/swap.sh
+++ b/metrics/swap.sh
@@ -3,11 +3,12 @@
 if is_osx; then
   collect () {
     report $(sysctl -n vm.swapusage |
-                awk '{ if ($3 == 0) exit; printf "%.1f", $6 / $3 * 100.0 }')
+              awk '{ if (int($3) == 0) exit; printf "%.1f", $6 / $3 * 100.0 }')
   }
 else
   collect () {
-    report $(free | awk '/Swap/{ printf "%.1f", $3/$2 * 100.0 }')
+    report $(free |
+        awk '/Swap/{ if (int($2) == 0) exit; printf "%.1f", $3 / $2 * 100.0 }')
   }
 fi
 
diff --git a/reporters/keen_io.sh b/reporters/keen_io.sh
new file mode 100644
index 0000000..65016fb
--- /dev/null
+++ b/reporters/keen_io.sh
@@ -0,0 +1,36 @@
+#!/bin/sh
+
+init() {
+  if [ -z $KEEN_IO_PROJECT_ID ]; then
+    echo "Error: keen_io requires \$KEEN_IO_PROJECT_ID to be set"
+    exit 1
+  fi
+
+  if [ -z $KEEN_IO_WRITE_KEY ]; then
+    echo "Error: keen_io requires \$KEEN_IO_WRITE_KEY to be set"
+    exit 1
+  fi
+
+  if [ -z $KEEN_IO_EVENT_COLLECTION ]; then
+    KEEN_IO_EVENT_COLLECTION=$HOSTNAME
+  fi
+
+  __keen_io_api_url="https://api.keen.io/3.0"
+  __keen_io_api_url+="/projects/$KEEN_IO_PROJECT_ID"
+  __keen_io_api_url+="/events/$KEEN_IO_EVENT_COLLECTION"
+  __keen_io_api_url+="?api_key=$KEEN_IO_WRITE_KEY"
+}
+
+report () {
+  METRIC=$1
+  VALUE=$2
+  curl -s $__keen_io_api_url -H "Content-Type: application/json" \
+                  -d "{\"metric\": \"$METRIC\", \"value\": $VALUE}" > /dev/null
+}
+
+docs () {
+  echo "Send data to Keen IO (https://keen.io)."
+  echo "\$KEEN_IO_WRITE_KEY=<write_key>"
+  echo "\$KEEN_IO_PROJECT_ID=<project_id>"
+  echo "\$KEEN_IO_EVENT_COLLECTION=$KEEN_IO_EVENT_COLLECTION"
+}
\ No newline at end of file
diff --git a/reporters/stathat.sh b/reporters/stathat.sh
index e584153..677467a 100644
--- a/reporters/stathat.sh
+++ b/reporters/stathat.sh
@@ -1,12 +1,20 @@
 #!/bin/sh
 
+init () {
+  if [ -z $STATHAT_API_KEY ]; then
+    echo "Error: stathat requires \$STATHAT_API_KEY to be set"
+    exit 1
+  fi
+}
+
 report () {
   METRIC=$1
   VALUE=$2
-  curl -d "stat=$METRIC&ezkey=$STATHAT_API_KEY&value=$VALUE" http://api.stathat.com/ez
+  curl -s -d "stat=$METRIC&ezkey=$STATHAT_API_KEY&value=$VALUE" \
+                                      http://api.stathat.com/ez > /dev/null
 }
 
 docs () {
   echo "Send data to StatHat (https://www.stathat.com)."
-  echo "\$API_KEY=<ez_key>"
+  echo "\$STATHAT_API_KEY=<ez_key>"
 }
\ No newline at end of file
diff --git a/sysmetricsd.sh b/sysmetricsd.sh
index b6b97d8..de7cfef 100755
--- a/sysmetricsd.sh
+++ b/sysmetricsd.sh
@@ -2,16 +2,16 @@
 
 # config
 INTERVAL=1
-REPORTER=stdout
+REPORTER=stdout # TODO: handle multiple reporters
 
 
 # handle opts
-opts_spec=":dvh-:"
+opts_spec=":dhvr:"
 opt_docs=false
 opt_verbose=false
 
 usage () {
-  echo "usage: $0 [-d] [-h]"
+  echo "usage: $0 [-d] [-h] [-v] [-r]"
 }
 
 help () {
@@ -23,13 +23,16 @@ while getopts "$opts_spec" opt; do
     d)
       opt_docs=true
       ;;
-    v)
-      opt_verbose=true
-      ;;
     h)
       help
       exit
       ;;
+    v)
+      opt_verbose=true
+      ;;
+    r)
+      REPORTER=$OPTARG
+      ;;
     *)
       usage
       exit 1
@@ -50,6 +53,7 @@ verbose "OS detected: $OS_TYPE"
 
 main_load
 verbose "Metrics loaded: ${__METRICS[@]}"
+verbose "Reporters loaded: ${REPORTER}"
 
 if [ "$opt_docs" = true ]; then
   main_docs