pstree命令可以使进程以tree的形式显示
pstree -s
systemd─┬─UVPHostd───6*[{UVPHostd}]
├─acpid
├─2*[agetty]
├─crond
├─dbus-daemon
├─dhclient
├─getosstat─┬─iostat
│ ├─pidstat
│ ├─sar───sadc
│ └─sleep
├─haveged
├─hirmd───3*[{hirmd}]
├─irqbalance───{irqbalance}
├─libvirtd───15*[{libvirtd}]
├─mcelog
├─ovs-vswitchd
├─ovsdb-server
├─python───{python}
├─rsyslogd───3*[{rsyslogd}]
├─smartd
├─sshd─┬─3*[sshd───sftp-server]
│ ├─sshd───bash───su───bash
│ └─sshd───bash───pstree
├─sysalarm───3*[{sysalarm}]
├─sysmonitor─┬─coredump_monito
│ ├─hotpatch_alarm.
│ ├─ipmi_monitor.py
│ ├─ovsdb_flows_bac
│ ├─3*[process_monitor]
│ ├─6*[python]
│ ├─sched_delay_mon
│ ├─systemd_monitor
│ ├─unetwork_alarm.───15*[{unetwork_alarm.}]
│ ├─vm_io_monitor.p
│ ├─vm_reboot_monit───{vm_reboot_monit}
│ └─18*[{sysmonitor}]
├─systemd-journal
├─systemd-logind
├─systemd-udevd
├─tuned───4*[{tuned}]
├─vBMC_agentd
└─virtlogd───{virtlogd}
-a, --arguments show command line arguments
-A, --ascii use ASCII line drawing characters
-c, --compact don't compact identical subtrees
-h, --highlight-all highlight current process and its ancestors
-H PID,
--highlight-pid=PID highlight this process and its ancestors
-g, --show-pgids show process group ids; implies -c
-G, --vt100 use VT100 line drawing characters
-l, --long don't truncate long lines
-n, --numeric-sort sort output by PID
-N type,
--ns-sort=type sort by namespace type (ipc, mnt, net, pid, user, uts)
-p, --show-pids show PIDs; implies -c
-s, --show-parents show parents of the selected process
-S, --ns-changes show namespace transitions
-u, --uid-changes show uid transitions
-U, --unicode use UTF-8 (Unicode) line drawing characters
-V, --version display version information
-Z,
--security-context show SELinux security contexts
PID start at this PID; default is 1 (init)
USER show only trees rooted at processes of this user