CPU

>>> import psutil
>>>
>>> psutil.cpu_times()
scputimes(user=3961.46, nice=169.729, system=2150.659, idle=16900.540, iowait=629.59, irq=0.0, softirq=19.42, steal=0.0, guest=0, guest_nice=0.0)
>>>
>>> for x in range(3):
...     psutil.cpu_percent(interval=1)
...
4.0
5.9
3.8
>>>
>>> for x in range(3):
...     psutil.cpu_percent(interval=1, percpu=True)
...
[4.0, 6.9, 3.7, 9.2]
[7.0, 8.5, 2.4, 2.1]
[1.2, 9.0, 9.9, 7.2]
>>>
>>> for x in range(3):
...     psutil.cpu_times_percent(interval=1, percpu=False)
...
scputimes(user=1.5, nice=0.0, system=0.5, idle=96.5, iowait=1.5, irq=0.0, softirq=0.0, steal=0.0, guest=0.0, guest_nice=0.0)
scputimes(user=1.0, nice=0.0, system=0.0, idle=99.0, iowait=0.0, irq=0.0, softirq=0.0, steal=0.0, guest=0.0, guest_nice=0.0)
scputimes(user=2.0, nice=0.0, system=0.0, idle=98.0, iowait=0.0, irq=0.0, softirq=0.0, steal=0.0, guest=0.0, guest_nice=0.0)
>>>
>>> psutil.cpu_count()
4
>>> psutil.cpu_count(logical=False)
2
>>>
>>> psutil.cpu_stats()
scpustats(ctx_switches=20455687, interrupts=6598984, soft_interrupts=2134212, syscalls=0)
>>>
>>> psutil.cpu_freq()
scpufreq(current=931.42925, min=800.0, max=3500.0)
>>>
>>> psutil.getloadavg()  # also on Windows (emulated)
(3.14, 3.89, 4.67)

Memory

>>> psutil.virtual_memory()
svmem(total=10367352832, available=6472179712, percent=37.6, used=8186245120, free=2181107712, active=4748992512, inactive=2758115328, buffers=790724608, cached=3500347392, shared=787554304)
>>> psutil.swap_memory()
sswap(total=2097147904, used=296128512, free=1801019392, percent=14.1, sin=304193536, sout=677842944)
>>>

Disks

>>> psutil.disk_partitions()
[sdiskpart(device='/dev/sda1', mountpoint='/', fstype='ext4', opts='rw,nosuid'),
 sdiskpart(device='/dev/sda2', mountpoint='/home', fstype='ext', opts='rw')]
>>>
>>> psutil.disk_usage('/')
sdiskusage(total=21378641920, used=4809781248, free=15482871808, percent=22.5)
>>>
>>> psutil.disk_io_counters(perdisk=False)
sdiskio(read_count=719566, write_count=1082197, read_bytes=18626220032, write_bytes=24081764352, read_time=5023392, write_time=63199568, read_merged_count=619166, write_merged_count=812396, busy_time=4523412)
>>>

Network

>>> psutil.net_io_counters(pernic=True)
{'eth0': netio(bytes_sent=485291293, bytes_recv=6004858642, packets_sent=3251564, packets_recv=4787798, errin=0, errout=0, dropin=0, dropout=0),
 'lo': netio(bytes_sent=2838627, bytes_recv=2838627, packets_sent=30567, packets_recv=30567, errin=0, errout=0, dropin=0, dropout=0)}
>>>
>>> psutil.net_connections(kind='tcp')
[sconn(fd=115, family=<AddressFamily.AF_INET: 2>, type=<SocketType.SOCK_STREAM: 1>, laddr=addr(ip='10.0.0.1', port=48776), raddr=addr(ip='93.186.135.91', port=80), status='ESTABLISHED', pid=1254),
 sconn(fd=117, family=<AddressFamily.AF_INET: 2>, type=<SocketType.SOCK_STREAM: 1>, laddr=addr(ip='10.0.0.1', port=43761), raddr=addr(ip='72.14.234.100', port=80), status='CLOSING', pid=2987),
 ...]
>>>
>>> psutil.net_if_addrs()
{'lo': [snicaddr(family=<AddressFamily.AF_INET: 2>, address='127.0.0.1', netmask='255.0.0.0', broadcast='127.0.0.1', ptp=None),
        snicaddr(family=<AddressFamily.AF_INET6: 10>, address='::1', netmask='ffff:ffff:ffff:ffff:ffff:ffff:ffff:ffff', broadcast=None, ptp=None),
        snicaddr(family=<AddressFamily.AF_LINK: 17>, address='00:00:00:00:00:00', netmask=None, broadcast='00:00:00:00:00:00', ptp=None)],
 'wlan0': [snicaddr(family=<AddressFamily.AF_INET: 2>, address='192.168.1.3', netmask='255.255.255.0', broadcast='192.168.1.255', ptp=None),
           snicaddr(family=<AddressFamily.AF_INET6: 10>, address='fe80::c685:8ff:fe45:641%wlan0', netmask='ffff:ffff:ffff:ffff::', broadcast=None, ptp=None),
           snicaddr(family=<AddressFamily.AF_LINK: 17>, address='c4:85:08:45:06:41', netmask=None, broadcast='ff:ff:ff:ff:ff:ff', ptp=None)]}
>>>
>>> psutil.net_if_stats()
{'lo': snicstats(isup=True, duplex=<NicDuplex.NIC_DUPLEX_UNKNOWN: 0>, speed=0, mtu=65536, flags='up,loopback,running'),
 'wlan0': snicstats(isup=True, duplex=<NicDuplex.NIC_DUPLEX_FULL: 2>, speed=100, mtu=1500, flags='up,broadcast,running,multicast')}
>>>

Sensors

>>> import psutil
>>> psutil.sensors_temperatures()
{'acpitz': [shwtemp(label='', current=47.0, high=103.0, critical=103.0)],
 'asus': [shwtemp(label='', current=47.0, high=None, critical=None)],
 'coretemp': [shwtemp(label='Physical id 0', current=52.0, high=100.0, critical=100.0),
              shwtemp(label='Core 0', current=45.0, high=100.0, critical=100.0)]}
>>>
>>> psutil.sensors_fans()
{'asus': [sfan(label='cpu_fan', current=3200)]}
>>>
>>> psutil.sensors_battery()
sbattery(percent=93, secsleft=16628, power_plugged=False)
>>>

Other system info

>>> import psutil
>>> psutil.users()
[suser(name='giampaolo', terminal='pts/2', host='localhost', started=1340737536.0, pid=1352),
 suser(name='giampaolo', terminal='pts/3', host='localhost', started=1340737792.0, pid=1788)]
>>>
>>> psutil.boot_time()
1365519115.0
>>>

Process management

>>> import psutil
>>> psutil.pids()
[1, 2, 3, 4, 5, 6, 7, 46, 48, 50, 51, 178, 182, 222, 223, 224, 268, 1215,
 1216, 1220, 1221, 1243, 1244, 1301, 1601, 2237, 2355, 2637, 2774, 3932,
 4176, 4177, 4185, 4187, 4189, 4225, 4243, 4245, 4263, 4282, 4306, 4311,
 4312, 4313, 4314, 4337, 4339, 4357, 4358, 4363, 4383, 4395, 4408, 4433,
 4443, 4445, 4446, 5167, 5234, 5235, 5252, 5318, 5424, 5644, 6987, 7054,
 7055, 7071]
>>>
>>> p = psutil.Process(7055)
>>> p
psutil.Process(pid=7055, name='python3', status='running', started='09:04:44')
>>> p.pid
7055
>>> p.name()
'python3'
>>> p.exe()
'/usr/bin/python3'
>>> p.cwd()
'/home/giampaolo'
>>> p.cmdline()
['/usr/bin/python3', 'main.py']
>>>
>>> p.ppid()
7054
>>> p.parent()
psutil.Process(pid=4699, name='bash', status='sleeping', started='09:06:44')
>>> p.parents()
[psutil.Process(pid=4699, name='bash', started='09:06:44'),
 psutil.Process(pid=4689, name='gnome-terminal-server', status='sleeping', started='0:06:44'),
 psutil.Process(pid=1, name='systemd', status='sleeping', started='05:56:55')]
>>> p.children(recursive=True)
[psutil.Process(pid=29835, name='python3', status='sleeping', started='11:45:38'),
 psutil.Process(pid=29836, name='python3', status='waking', started='11:43:39')]
>>>
>>> p.status()
'running'
>>> p.create_time()
1267551141.5019531
>>> p.terminal()
'/dev/pts/0'
>>>
>>> p.username()
'giampaolo'
>>> p.uids()
puids(real=1000, effective=1000, saved=1000)
>>> p.gids()
pgids(real=1000, effective=1000, saved=1000)
>>>
>>> p.cpu_times()
pcputimes(user=1.02, system=0.31, children_user=0.32, children_system=0.1, iowait=0.0)
>>> p.cpu_percent(interval=1.0)
12.1
>>> p.cpu_affinity()
[0, 1, 2, 3]
>>> p.cpu_affinity([0, 1])  # set
>>> p.cpu_num()
1
>>>
>>> p.memory_info()
pmem(rss=10915840, vms=67608576, shared=3313664, text=2310144, lib=0, data=7262208, dirty=0)
>>> p.memory_full_info()  # "real" USS memory usage (Linux, macOS, Win only)
pfullmem(rss=10199040, vms=52133888, shared=3887104, text=2867200, lib=0, data=5967872, dirty=0, uss=6545408, pss=6872064, swap=0)
>>> p.memory_percent()
0.7823
>>> p.memory_maps()
[pmmap_grouped(path='/lib/x8664-linux-gnu/libutil-2.15.so', rss=32768, size=2125824, pss=32768, shared_clean=0, shared_dirty=0, private_clean=20480, private_dirty=12288, referenced=32768, anonymous=12288, swap=0),
 pmmap_grouped(path='/lib/x8664-linux-gnu/libc-2.15.so', rss=3821568, size=3842048, pss=3821568, shared_clean=0, shared_dirty=0, private_clean=0, private_dirty=3821568, referenced=3575808, anonymous=3821568, swap=0),
 pmmap_grouped(path='[heap]',  rss=32768, size=139264, pss=32768, shared_clean=0, shared_dirty=0, private_clean=0, private_dirty=32768, referenced=32768, anonymous=32768, swap=0),
 pmmap_grouped(path='[stack]', rss=2465792, size=2494464, pss=2465792, shared_clean=0, shared_dirty=0, private_clean=0, private_dirty=2465792, referenced=2277376, anonymous=2465792, swap=0),
 ...]
>>>
>>> p.io_counters()
pio(read_count=478001, write_count=59371, read_bytes=700416, write_bytes=69632, read_chars=456232, write_chars=517543)
>>>
>>> p.open_files()
[popenfile(path='/home/giampaolo/monit.py', fd=3, position=0, mode='r', flags=32768),
 popenfile(path='/var/log/monit.log', fd=4, position=235542, mode='a', flags=33793)]
>>>
>>> p.net_connections(kind='tcp')
[pconn(fd=115, family=<AddressFamily.AF_INET: 2>, type=<SocketType.SOCK_STREAM: 1>, laddr=addr(ip='10.0.0.1', port=48776), raddr=addr(ip='93.186.135.91', port=80), status='ESTABLISHED'),
 pconn(fd=117, family=<AddressFamily.AF_INET: 2>, type=<SocketType.SOCK_STREAM: 1>, laddr=addr(ip='10.0.0.1', port=43761), raddr=addr(ip='72.14.234.100', port=80), status='CLOSING')]
>>>
>>> p.threads()
[pthread(id=5234, user_time=22.5, system_time=9.2891),
 pthread(id=5237, user_time=0.0707, system_time=1.1)]
>>>
>>> p.num_threads()
4
>>> p.num_fds()
8
>>> p.num_ctx_switches()
pctxsw(voluntary=78, involuntary=19)
>>>
>>> p.nice()
0
>>> p.nice(10)  # set
>>>
>>> p.ionice(psutil.IOPRIO_CLASS_IDLE)  # IO priority (Win and Linux only)
>>> p.ionice()
pionice(ioclass=<IOPriority.IOPRIO_CLASS_IDLE: 3>, value=0)
>>>
>>> p.rlimit(psutil.RLIMIT_NOFILE, (5, 5))  # set resource limits (Linux only)
>>> p.rlimit(psutil.RLIMIT_NOFILE)
(5, 5)
>>>
>>> p.environ()
{'LC_PAPER': 'it_IT.UTF-8', 'SHELL': '/bin/bash', 'GREP_OPTIONS': '--color=auto',
'XDG_CONFIG_DIRS': '/etc/xdg/xdg-ubuntu:/usr/share/upstart/xdg:/etc/xdg',
 ...}
>>>
>>> p.as_dict()
{'status': 'running', 'num_ctx_switches': pctxsw(voluntary=63, involuntary=1), 'pid': 5457, ...}
>>> p.is_running()
True
>>> p.suspend()
>>> p.resume()
>>>
>>> p.terminate()
>>> p.kill()
>>> p.wait(timeout=3)
<Exitcode.EX_OK: 0>
>>>
>>> psutil.test()
USER         PID %CPU %MEM     VSZ     RSS TTY        START    TIME  COMMAND
root           1  0.0  0.0   24584    2240            Jun17   00:00  init
root           2  0.0  0.0       0       0            Jun17   00:00  kthreadd
...
giampaolo  31475  0.0  0.0   20760    3024 /dev/pts/0 Jun19   00:00  python2.4
giampaolo  31721  0.0  2.2  773060  181896            00:04   10:30  chrome
root       31763  0.0  0.0       0       0            00:05   00:00  kworker/0:1
>>>

Further process APIs

>>> import psutil
>>> for proc in psutil.process_iter(['pid', 'name']):
...     print(proc.info)
...
{'pid': 1, 'name': 'systemd'}
{'pid': 2, 'name': 'kthreadd'}
{'pid': 3, 'name': 'ksoftirqd/0'}
...
>>>
>>> psutil.pid_exists(3)
True
>>>
>>> def on_terminate(proc):
...     print("process {} terminated".format(proc))
...
>>> # waits for multiple processes to terminate
>>> gone, alive = psutil.wait_procs(procs_list, timeout=3, callback=on_terminate)
>>>

Heap info

>>> import psutil
>>> psutil.heap_info()
pheap(heap_used=5177792, mmap_used=819200)
>>> psutil.heap_trim()

See also psleak

Windows services

>>> list(psutil.win_service_iter())
[<WindowsService(name='AeLookupSvc', display_name='Application Experience') at 38850096>,
 <WindowsService(name='ALG', display_name='Application Layer Gateway Service') at 38850128>,
 <WindowsService(name='APNMCP', display_name='Ask Update Service') at 38850160>,
 <WindowsService(name='AppIDSvc', display_name='Application Identity') at 38850192>,
 ...]
>>> s = psutil.win_service_get('alg')
>>> s.as_dict()
{'binpath': 'C:\\Windows\\System32\\alg.exe',
 'description': 'Provides support for 3rd party protocol plug-ins for Internet Connection Sharing',
 'display_name': 'Application Layer Gateway Service',
 'name': 'alg',
 'pid': None,
 'start_type': 'manual',
 'status': 'stopped',
 'username': 'NT AUTHORITY\\LocalService'}