diff -r 000000000000 -r 6474c204b198 python/psutil/examples/top.py
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/python/psutil/examples/top.py	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,202 @@
+#!/usr/bin/env python
+
+# Copyright (c) 2009, Giampaolo Rodola'. All rights reserved.
+# Use of this source code is governed by a BSD-style license that can be
+# found in the LICENSE file.
+
+"""
+A clone of top / htop.
+
+Author: Giampaolo Rodola' <g.rodola@gmail.com>
+"""
+
+import os
+import sys
+if os.name != 'posix':
+    sys.exit('platform not supported')
+import time
+import curses
+import atexit
+from datetime import datetime, timedelta
+
+import psutil
+
+
+# --- curses stuff
+def tear_down():
+    win.keypad(0)
+    curses.nocbreak()
+    curses.echo()
+    curses.endwin()
+
+win = curses.initscr()
+atexit.register(tear_down)
+curses.endwin()
+lineno = 0
+
+def print_line(line, highlight=False):
+    """A thin wrapper around curses's addstr()."""
+    global lineno
+    try:
+        if highlight:
+            line += " " * (win.getmaxyx()[1] - len(line))
+            win.addstr(lineno, 0, line, curses.A_REVERSE)
+        else:
+            win.addstr(lineno, 0, line, 0)
+    except curses.error:
+        lineno = 0
+        win.refresh()
+        raise
+    else:
+        lineno += 1
+# --- /curses stuff
+
+
+def bytes2human(n):
+    """
+    >>> bytes2human(10000)
+    '9K'
+    >>> bytes2human(100001221)
+    '95M'
+    """
+    symbols = ('K', 'M', 'G', 'T', 'P', 'E', 'Z', 'Y')
+    prefix = {}
+    for i, s in enumerate(symbols):
+        prefix[s] = 1 << (i+1)*10
+    for s in reversed(symbols):
+        if n >= prefix[s]:
+            value = int(float(n) / prefix[s])
+            return '%s%s' % (value, s)
+    return "%sB" % n
+
+def poll(interval):
+    # sleep some time
+    time.sleep(interval)
+    procs = []
+    procs_status = {}
+    for p in psutil.process_iter():
+        try:
+            p.dict = p.as_dict(['username', 'get_nice', 'get_memory_info',
+                                'get_memory_percent', 'get_cpu_percent',
+                                'get_cpu_times', 'name', 'status'])
+            try:
+                procs_status[str(p.dict['status'])] += 1
+            except KeyError:
+                procs_status[str(p.dict['status'])] = 1
+        except psutil.NoSuchProcess:
+            pass
+        else:
+            procs.append(p)
+
+    # return processes sorted by CPU percent usage
+    processes = sorted(procs, key=lambda p: p.dict['cpu_percent'], reverse=True)
+    return (processes, procs_status)
+
+def print_header(procs_status, num_procs):
+    """Print system-related info, above the process list."""
+
+    def get_dashes(perc):
+        dashes =  "|" * int((float(perc) / 10 * 4))
+        empty_dashes = " " * (40 - len(dashes))
+        return dashes, empty_dashes
+
+    # cpu usage
+    for cpu_num, perc in enumerate(psutil.cpu_percent(interval=0, percpu=True)):
+        dashes, empty_dashes = get_dashes(perc)
+        print_line(" CPU%-2s [%s%s] %5s%%" % (cpu_num, dashes, empty_dashes,
+                                              perc))
+    mem = psutil.virtual_memory()
+    dashes, empty_dashes = get_dashes(mem.percent)
+    used = mem.total - mem.available
+    line = " Mem   [%s%s] %5s%% %6s/%s" % (
+        dashes, empty_dashes,
+        mem.percent,
+        str(int(used / 1024 / 1024)) + "M",
+        str(int(mem.total / 1024 / 1024)) + "M"
+    )
+    print_line(line)
+
+    # swap usage
+    swap = psutil.swap_memory()
+    dashes, empty_dashes = get_dashes(swap.percent)
+    line = " Swap  [%s%s] %5s%% %6s/%s" % (
+        dashes, empty_dashes,
+        swap.percent,
+        str(int(swap.used / 1024 / 1024)) + "M",
+        str(int(swap.total / 1024 / 1024)) + "M"
+    )
+    print_line(line)
+
+    # processes number and status
+    st = []
+    for x, y in procs_status.items():
+        if y:
+            st.append("%s=%s" % (x, y))
+    st.sort(key=lambda x: x[:3] in ('run', 'sle'), reverse=1)
+    print_line(" Processes: %s (%s)" % (num_procs, ' '.join(st)))
+    # load average, uptime
+    uptime = datetime.now() - datetime.fromtimestamp(psutil.BOOT_TIME)
+    av1, av2, av3 = os.getloadavg()
+    line = " Load average: %.2f %.2f %.2f  Uptime: %s" \
+            % (av1, av2, av3, str(uptime).split('.')[0])
+    print_line(line)
+
+def refresh_window(procs, procs_status):
+    """Print results on screen by using curses."""
+    curses.endwin()
+    templ = "%-6s %-8s %4s %5s %5s %6s %4s %9s  %2s"
+    win.erase()
+    header = templ % ("PID", "USER", "NI", "VIRT", "RES", "CPU%", "MEM%",
+                      "TIME+", "NAME")
+    print_header(procs_status, len(procs))
+    print_line("")
+    print_line(header, highlight=True)
+    for p in procs:
+        # TIME+ column shows process CPU cumulative time and it
+        # is expressed as: "mm:ss.ms"
+        if p.dict['cpu_times'] != None:
+            ctime = timedelta(seconds=sum(p.dict['cpu_times']))
+            ctime = "%s:%s.%s" % (ctime.seconds // 60 % 60,
+                                  str((ctime.seconds % 60)).zfill(2),
+                                  str(ctime.microseconds)[:2])
+        else:
+            ctime = ''
+        if p.dict['memory_percent'] is not None:
+            p.dict['memory_percent'] = round(p.dict['memory_percent'], 1)
+        else:
+            p.dict['memory_percent'] = ''
+        if p.dict['cpu_percent'] is None:
+            p.dict['cpu_percent'] = ''
+        if p.dict['username']:
+            username = p.dict['username'][:8]
+        else:
+            username = ""
+        line = templ % (p.pid,
+                        username,
+                        p.dict['nice'],
+                        bytes2human(getattr(p.dict['memory_info'], 'vms', 0)),
+                        bytes2human(getattr(p.dict['memory_info'], 'rss', 0)),
+                        p.dict['cpu_percent'],
+                        p.dict['memory_percent'],
+                        ctime,
+                        p.dict['name'] or '',
+                        )
+        try:
+            print_line(line)
+        except curses.error:
+            break
+        win.refresh()
+
+
+def main():
+    try:
+        interval = 0
+        while 1:
+            args = poll(interval)
+            refresh_window(*args)
+            interval = 1
+    except (KeyboardInterrupt, SystemExit):
+        pass
+
+if __name__ == '__main__':
+    main()