diff --git a/.gitignore b/.gitignore
index 3481463..c91ba74 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1,2 +1,3 @@
 nimcache/
 ptk
+*.sw?
diff --git a/ptk.nim b/ptk.nim
index e8fbbe0..f08e030 100644
--- a/ptk.nim
+++ b/ptk.nim
@@ -4,12 +4,15 @@
 ## Simple time keeping CLI
 
 import algorithm, docopt, json, langutils, logging, os, sequtils, strutils,
-  tempfile, times, uuids
+  tempfile, terminal, times, timeutils, uuids
+import ptkutil
 
 type
   Mark* = tuple[id: UUID, time: TimeInfo, summary: string, notes: string]
   Timeline* = tuple[name: string, marks: seq[Mark]]
 
+const STOP_MSG = "STOP"
+
 let NO_MARK: Mark = (
   id: parseUUID("00000000-0000-0000-0000-000000000000"),
   time: getLocalTime(getTime()),
@@ -28,7 +31,6 @@ proc exitErr(msg: string): void =
   fatal "ptk: " & msg
   quit(QuitFailure)
 
-
 proc parseTime(timeStr: string): TimeInfo =
   for fmt in TIME_FORMATS:
     try: return parse(timeStr, fmt)
@@ -73,25 +75,80 @@ proc saveTimeline(timeline: Timeline, location: string): void =
   except: raise newException(IOError, "unable to save changes to " & location)
   finally: close(timelineFile)
 
+proc flexFormat(i: TimeInterval): string =
+  let fmt =
+    if i > 1.days: "d'd' H'h' m'm'"
+    elif i >= 1.hours: "H'h' m'm'"
+    elif i >= 1.minutes: "m'm' s's'"
+    else: "s's'"
+
+  return i.format(fmt)
+
+proc writeMarks(marks: seq[Mark], includeNotes = false): void =
+  let now = getLocalTime(getTime())
+
+  let timeFormat =
+    if now - marks.first.time > 1.years: "yyyy-MM-dd HH:mm"
+    elif now - marks.first.time > 7.days: "MMM dd HH:mm"
+    elif now - marks.first.time > 1.days: "ddd HH:mm"
+    else: "HH:mm"
+
+  var intervals: seq[TimeInterval] = @[]
+  for i in 0..<marks.len - 1: intervals.add(marks[i+1].time - marks[i].time)
+  intervals.add(now - marks.last.time)
+
+  var prefixLens: seq[int] = @[]
+  var longestPrefix = 0
+  for i in 0..<marks.len:
+    let
+      mark = marks[i]
+      interval = intervals[i]
+      prefix = ($mark.id)[0..<8] & "  " & mark.time.format(timeFormat) & " (" & interval.flexFormat & ")"
+
+    prefixLens.add(prefix.len)
+    if prefix.len > longestPrefix: longestPrefix = prefix.len
+
+  for i in 0..<marks.len:
+    let mark = marks[i]
+
+    if mark.summary == STOP_MSG: continue
+
+    let duration = intervals[i].flexFormat
+    setForegroundColor(stdout, fgBlack, true)
+    write(stdout, ($mark.id)[0..<8])
+    setForegroundColor(stdout, fgYellow)
+    write(stdout, "  " & mark.time.format(timeFormat))
+    setForegroundColor(stdout, fgCyan)
+    write(stdout, " (" & duration & ")")
+    resetAttributes(stdout)
+    writeLine(stdout, spaces(longestPrefix - prefixLens[i]) & " -- " & mark.summary)
+
+    if includeNotes and len(mark.notes.strip) > 0:
+      writeLine(stdout, spaces(longestPrefix) & mark.notes)
+      writeLine(stdout, "")
+
 proc formatMark(mark: Mark, nextMark = NO_MARK, timeFormat = ISO_TIME_FORMAT, includeNotes = false): string =
 
   let nextTime =
     if nextMark == NO_MARK: getLocalTime(getTime())
-    else: mark.time
+    else: nextMark.time
 
+  let duration = (nextTime - mark.time).flexFormat
   # TODO: pick up here calculating the time between marks
 
-  let prefix = ($mark.id)[0..<8] & "  " & mark.time.format(timeFormat) & "  " 
+  let prefix = ($mark.id)[0..<8] & "  " & mark.time.format(timeFormat) & " (" & duration & ") -- "
+  let prefixLen = len(($mark.id)[0..<8] & "  " & mark.time.format(timeFormat) & " (" & duration & ") -- ")
+
   result = prefix & mark.summary
   if includeNotes and len(mark.notes.strip()) > 0:
-    let wrappedNotes = wordWrap(s = mark.notes, maxLineWidth = 80 - len(prefix))
+    let wrappedNotes = wordWrap(s = mark.notes, maxLineWidth = 80 - prefixLen)
     for line in splitLines(wrappedNotes):
-      result &= "\x0D\x0A" & spaces(len(prefix)) & line
+      result &= "\x0D\x0A" & spaces(prefixLen) & line
     result &= "\x0D\x0A"
 
-proc findMarkById(timeline: Timeline, id: string): auto =
+proc findById(marks: seq[Mark], id: string): auto =
   var idx = 0
-  for mark in timeline.marks:
+  for mark in marks:
     if startsWith($mark.id, id): return (mark, idx)
     inc(idx)
 
@@ -103,7 +160,7 @@ proc doInit(timelineLocation: string): void =
   let name = stdin.readLine()
 
   let timeline = %*
-    { "name": if name.len > 0: name else: "New Timeline",
+    { "name": if name.strip.len > 0: name.strip else: "New Timeline",
       "marks": [] }
       #"createdAt": getLocalTime().format("yyyy-MM-dd'T'HH:mm:ss") }
 
@@ -152,29 +209,40 @@ Usage:
   ptk init [options]
   ptk add [options]
   ptk add [options] <summary>
-  ptk list [options] [<start>] [<end>]
   ptk ammend [options] <id> [<summary>]
+  ptk stop [options]
+  ptk continue
   ptk delete <id>
+  ptk list [options]
+  ptk sum-time --ids <ids>...
+  ptk sum-time [options] [<firstId>] [<lastId>]
   ptk (-V | --version)
   ptk (-h | --help)
 
 Options:
 
-  -f --file   <file>      Use the given time keeper file.
+  -f --file <file>        Use the given timeline file.
   -c --config <cfgFile>   Use <cfgFile> as configuration for the CLI.
   -t --time <time>        For add and ammend, use this time instead of the current time.
   -n --notes <notes>      For add and ammend, set the notes for a time mark.
   -V --version            Print the tool's version information.
   -e --edit               Open the mark in an editor.
+  -a --after <after>      Restrict the selection to marks after <after>.
+  -b --before <before>    Restrict the selection to marks after <before>.
   -h --help               Print this usage information.
   -v --verbose            Include notes in timeline entry output.
+  -E --echo-args          Echo the program's understanding of it's arguments.
 """
 
+# TODO: add    ptk delete [options]
+
   logging.addHandler(newConsoleLogger())
 
   # Parse arguments
   let args = docopt(doc, version = "ptk 0.1.0")
 
+  if args["--echo-args"]: echo $args
+
   if args["--help"]:
     echo doc
     quit()
@@ -194,7 +262,7 @@ Options:
     ptkrcFilename = $getEnv("HOME") & "/.ptkrc"
     try:
       cfgFile = open(ptkrcFilename, fmWrite)
-      cfgFile.write("{}")
+      cfgFile.write("{\"timelineLogFile\": \"timeline.log.json\"}")
     except: warn "ptk: could not write default .ptkrc to " & ptkrcFilename
     finally: close(cfgFile)
 
@@ -223,43 +291,75 @@ Options:
       raise newException(IOError,
         "time log file doesn't exist: " & timelineLocation)
 
-    var timeline = parseFile(timelineLocation)
+    var timeline = loadTimeline(timelineLocation)
+
+    if args["stop"]:
+
+      let newMark = (
+        id: genUUID(),
+        time:
+          if args["--time"]: parseTime($args["--time"])
+          else: getLocalTime(getTime()),
+        summary: STOP_MSG,
+        notes: args["--notes"] ?: "")
+        
+      timeline.marks.add(newMark)
+      writeMarks(
+        marks = timeline.marks[timeline.marks.len - 2..<timeline.marks.len],
+        includeNotes = args["--verbose"])
+      echo "stopped timer"
+
+      saveTimeline(timeline, timelineLocation)
+
+    if args["continue"]:
+
+      if timeline.marks.last.summary != STOP_MSG:
+        echo "There is already something in progress:"
+        writeMarks(
+          marks = @[timeline.marks.last],
+          includeNotes = args["--verbose"])
+        quit(0)
+
+      let prevMark = timeline.marks[timeline.marks.len - 2]
+      var newMark: Mark = (
+        id: genUUID(),
+        time:
+          if args["--time"]: parseTime($args["--time"])
+          else: getLocalTime(getTime()),
+        summary: prevMark.summary,
+        notes: prevMark.notes)
+
+      timeline.marks.add(newMark)
+      writeMarks(marks = @[newMark], includeNotes = args["--verbose"])
+
+      saveTimeline(timeline, timelineLocation)
 
     if args["add"]:
 
       var newMark: Mark = (
         id: genUUID(),
         time:
-          if args["--time"]: parseTime($args["<time>"])
+          if args["--time"]: parseTime($args["--time"])
           else: getLocalTime(getTime()),
         summary: args["<summary>"] ?: "",
         notes: args["--notes"] ?: "")
 
       if args["--edit"]: edit(newMark)
 
-      timeline["marks"].add(%newMark)
-      echo formatMark(
-        mark = newMark,
-        timeFormat = "HH:mm",
-        includeNotes = args["--verbose"])
+      timeline.marks.add(newMark)
+      writeMarks(marks = @[newMark], includeNotes = args["--verbose"])
 
-      var timelineFile: File
-      try:
-        timelineFile = open(timelineLocation, fmWrite)
-        timelineFile.writeLine(pretty(%timeline))
-      finally: close(timelineFile)
+      saveTimeline(timeline, timelineLocation)
 
     if args["ammend"]:
 
-      var timeline = loadTimeline(timelineLocation)
-
       # Note, this returns a copy, not a reference to the mark in the seq.
-      var (mark, markIdx) = timeline.findMarkById($args["<id>"])
+      var (mark, markIdx) = timeline.marks.findById($args["<id>"])
       
       if args["<summary>"]: mark.summary = $args["<summary>"]
       if args["--notes"]: mark.notes = $args["<notes>"]
       if args["--time"]:
-        try: mark.time = parseTime($args["<time>"])
+        try: mark.time = parseTime($args["--time"])
         except: raise newException(ValueError,
           "invalid value for --time: " & getCurrentExceptionMsg())
 
@@ -276,41 +376,93 @@ Options:
 
     if args["delete"]:
 
-      var timeline = loadTimeline(timelineLocation)
-
-      var (mark, markIdx) = timeline.findMarkById($args["<id>"])
+      var (mark, markIdx) = timeline.marks.findById($args["<id>"])
       timeline.marks.delete(markIdx)
       saveTimeline(timeline, timelineLocation)
 
     if args["list"]:
 
-      let timeline = loadTimeline(timelineLocation)
-
       var marks = timeline.marks
 
-      if args["<start>"]:
-        var startTime: Time
-        try: startTime = parseTime($args["<start>"]).toTime
+      if args["--after"]:
+        var startTime: TimeInfo
+        try: startTime = parseTime($args["--after"])
         except: raise newException(ValueError,
-          "invalid value for --start: " & getCurrentExceptionMsg())
-        marks = marks.filter(proc(m: Mark): bool = m.time.toTime > startTime)
+          "invalid value for --after: " & getCurrentExceptionMsg())
+        marks = marks.filter(proc(m: Mark): bool = m.time > startTime)
 
-      if args["<end>"]:
-        var endTime: Time
-        try: endTime = parseTime($args["<end>"]).toTime
+      if args["--before"]:
+        var endTime: TimeInfo
+        try: endTime = parseTime($args["--before"])
         except: raise newException(ValueError,
-          "invalid value for --end: " & getCurrentExceptionMsg())
-        marks = marks.filter(proc(m: Mark): bool = m.time.toTime < endTime)
+          "invalid value for --before: " & getCurrentExceptionMsg())
+        marks = marks.filter(proc(m: Mark): bool = m.time < endTime)
 
-      marks = marks.sorted(proc(a, b: Mark): int = cast[int](a.time.toTime - b.time.toTime))
+      marks = marks.sorted(proc(a, b: Mark): int = cmp(a.time, b.time))
 
-      #for i in 0..<marks.high-1:
-      #  echo formatMark(
-      for mark in marks:
-        echo formatMark(
-          mark = mark,
-          timeFormat = "HH:mm",
-          includeNotes = args["--verbose"])
+      writeMarks(marks = marks, includeNotes = args["--version"])
+
+    if args["sum-time"]:
+    
+      var intervals: seq[TimeInterval] = @[]
+
+      if args["--ids"]:
+        for id in args["<ids>"]:
+          let (mark, markIdx) = timeline.marks.findById(id)
+          if mark == NO_MARK:
+            warn "ptk: could not find mark for id " & id
+          elif markIdx == timeline.marks.len - 1:
+            intervals.add(getLocalTime(getTime()) - mark.time)
+          else:
+            intervals.add(timeline.marks[markIdx + 1].time - mark.time)
+
+      else:
+
+        var startIdx = 0
+        var endIdx = timeline.marks.len - 1
+
+        if args["<firstId>"]:
+          startIdx = max(timeline.marks.findById($args["<firstId>"])[1], 0)
+
+        if args["<lastId>"]:
+          let idx = timeline.marks.findById($args["<firstId>"])[1]
+          if (idx > 0): endIdx = idx
+
+        if args["--after"]:
+          var startTime: TimeInfo
+          try: startTime = parseTime($args["--after"])
+          except: raise newException(ValueError,
+            "invalid value for --after: " & getCurrentExceptionMsg())
+          let marks = timeline.marks.filter(proc(m: Mark): bool = m.time > startTime)
+
+          let (mark, idx) = timeline.marks.findById($marks.first.id)
+          if idx > startIdx: startIdx = idx
+
+        if args["--before"]:
+          var endTime: TimeInfo
+          try: endTime = parseTime($args["--before"])
+          except: raise newException(ValueError,
+            "invalid value for --after: " & getCurrentExceptionMsg())
+          let marks = timeline.marks.filter(proc(m: Mark): bool = m.time < endTime)
+
+          let (mark, idx) = timeline.marks.findById($marks.last.id)
+          if idx < endIdx: endIdx = idx
+
+        for idx in startIdx..<min(endIdx, timeline.marks.len - 1):
+          if timeline.marks[idx].summary == STOP_MSG: continue # don't count stops
+          intervals.add(timeline.marks[idx + 1].time - timeline.marks[idx].time)
+
+        if endIdx == timeline.marks.len - 1 and
+           timeline.marks.last.summary != STOP_MSG:
+          intervals.add(getLocalTime(getTime()) - timeline.marks.last.time)
+
+      if intervals.len == 0:
+        echo "ptk: no marks found"
+
+      else:
+        let total = foldl(intervals, a + b)
+        echo total.flexFormat
+ 
  except:
   fatal "ptk: " & getCurrentExceptionMsg()
   quit(QuitFailure)
diff --git a/ptk.nimble b/ptk.nimble
index 64d7965..7fd0238 100644
--- a/ptk.nimble
+++ b/ptk.nimble
@@ -8,5 +8,5 @@ bin           = @["ptk"]
 
 # Dependencies
 
-requires @["nim >= 0.15.0", "docopt >= 0.6.4", "uuids", "langutils", "tempfile"]
+requires @["nim >= 0.15.0", "docopt >= 0.6.4", "uuids", "langutils", "tempfile", "timeutils"]
 
diff --git a/ptkutil.nim b/ptkutil.nim
new file mode 100644
index 0000000..50a025f
--- /dev/null
+++ b/ptkutil.nim
@@ -0,0 +1,3 @@
+template first*(s: seq): auto = s[0]
+
+template last*(s: seq): auto = s[len(s)-1]