Linux shell编程学习笔记61： pstree 命令——显示进程树

0 前言

在

Linux shell编程学习笔记59： ps 获取系统进程信息，类似于Windows系统中的tasklist 命令https://blog.csdn.net/Purpleendurer/article/details/139696466?spm=1001.2014.3001.5501

中我们研究了ps命令。在Linux中，通过ps命令，我们可以查看系统中运行的进程信息，包括进程的ID、父进程ID、CPU和内存占用等信息。不过ps命令显示的进程信息中，进程间的父子关系还不够直观。

Linux还提供了pstree命令，可以以树的形式直观地显示进程间的关系。

1 pstree 命令 的功能、格式和选项说明

我们先看一下pstree命令的帮助信息。

pstree命令 不支持 --help选项。

[purpleendurer @ bash ~] pstree --help
pstree: 未知的选项 `--help'
Usage: pstree [ -a ] [ -c ] [ -h | -H PID ] [ -l ] [ -n ] [ -p ] [ -g ] [ -u ]
              [ -A | -G | -U ] [ PID | USER ]
       pstree -V
Display a tree of processes.

  -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     show         SELinux security contexts
  PID    start at this PID; default is 1 (init)
  USER   show only trees rooted at processes of this user

[purpleendurer @ bash ~] 

1.1 pstree 命令 的功能

显示进程树（Display a tree of processes）。

1.2 pstree命令的格式

ps [选项] [PID | USER]

或

ps -V

1.3 pstree命令的选项

选项功能
-a

--arguments
显示进程对应命令行有参数，如果是被记忆体置换出去的进程则会加上括号
-A

--ascii
使用ASCII码线条绘制字符
-c

--compact
如果有重复的进程名, 则分开列出（预设值是会在前面加上 *）
-h

--highlight-all
突出显示当前流程及其祖先
-H PID

--highlight-pid=PID
突出显示指定PID的过程及其祖先
-g

--show-pgids
显示进程组 ID;隐含 -c
-G

--vt100
使用 VT100 线条绘制字符
-l

--long
不要截断长线
-n

--numeric-sort
按 PID 对输出进行排序
-N type

--ns-sort=type
按命名空间类型排序（IPC、MNT、NET、PID、USER、UTS）
-p

--show-pids
显示 PID;隐含 -c
-s

--show-parents
显示所选进程的父进程
-S

--ns-changes
显示命名空间转换
-u

--uid-changes
显示 UID 转换
-U

--unicode
使用 UTF-8 （Unicode） 线条绘制字符
-V

--version
显示版本信息

1.3 pstree命令的参数

参数说明PID从指定的PID开始，默认值为1USER以指定用户显示进程树

2 pstree命令实列

2.1 pstree | more 分页显示进程树

[purpleendurer @ bash ~] pstree | more
systemd-+-ETSMJBZGN0---3*[{ETSMJBZGN0}]
        |-ETSMJBZGN10
        |-ETSMJBZUI1-+-29*[QOperationLogTh]
        |            |-11*[QRemoveLabelThr]
        |            |-{QFunctionPipe}
        |            |-{QKeepSessionThr}
        |            |-2*[{QOperationLogTh}]
        |            |-{QPluginOutPipe}
        |            |-{QProcessManager}
        |            |-{QRightMenuPipe}
        |            `-{QSLPluginPipe}
        |-ETSMJBZUI11---8*[{ThreadServer}]
        |-ETSMJBZUI13---sleep
        |-ETSMJBZWJTX0---{ETSMJBZWJTX0}
        |-2*[ETSMJBZWJTX1]
        |-FoxitOfficeSuit---FoxitOfficeSuit-+-FoxitUpgrade
        |                                   `-3*[{FoxitOfficeSuit}]
        |-NetworkManager-+-dhclient
        |                |-dnsmasq
        |                |-{gdbus}
        |                `-{gmain}
        |-PNXClientHost.o---PNXClientHost.o
        |-SuwellUpdateSer
        |-WLHXXYCGN701
        |-WLHXXYCGN702---{WLHXXYCGN702}
        |-WLHXXYCGN802
        |-accounts-daemon-+-{gdbus}
        |                 `-{gmain}
        |-acpid
        |-activation-daem
        |-2*[agetty]
        |-aptd---{gmain}
        |-auditd---{auditd}
        |-avahi-daemon---avahi-daemon
        |-backup-daemon---{QDBusConnection}
        |-biometric-authe-+-2*[{biometric-authe}]
        |                 |-{gdbus}
        |                 `-{gmain}
        |-2*[cat]
--更多--

2.2 pstree -apn | more ：用ASCII码线条绘制字符显示在运行的进程树，包括命令参数和PID

[purpleendurer @ bash ~] pstree -apn | more
systemd,1 splash
  |-sqaxsafeforcnos,367 --minishow
  |   |-{QXcbEventReader},371
  |   |-{llvmpipe-0},386
  |   |-{llvmpipe-1},387
  |   |-{llvmpipe-2},388
  |   |-{llvmpipe-3},389
  |   |-{QDBusConnection},390
  |   |-{gmain},415
  |   |-{gdbus},416
  |   |-{CASocketThread},428
  |   |-{sqaxsafeforcnos},432
  |   |-{sqaxsafeforcnos},433
  |   |-{sqaxsafeforcnos},434
  |   |-{sqaxsafeforcnos},435
  |   |-{sqaxsafeforcnos},436
  |   |-{sqaxsafeforcnos},437
  |   |-{sqaxsafeforcnos},438
  |   |-{sqaxsafeforcnos},439
  |   |-{sqaxsafeforcnos},497
  |   |-{sqaxsafeforcnos},498
  |   |-{sqaxsafeforcnos},499
  |   |-{sqaxsafeforcnos},500
  |   |-{sqaxsafeforcnos},501
  |   |-{sqaxsafeforcnos},502
  |   |-{sqaxsafeforcnos},503
  |   |-{sqaxsafeforcnos},504
  |   |-{sqaxsafeforcnos},506
  |   |-{sqaxsafeforcnos},507
  |   |-{sqaxsafeforcnos},508
  |   |-{sqaxsafeforcnos},509
  |   |-{sqaxsafeforcnos},510
  |   |-{sqaxsafeforcnos},511
  |   |-{sqaxsafeforcnos},512
  |   |-{sqaxsafeforcnos},516
  |   |-{XTableThread},520
  |   |-{SpeedCtrl},522
  |   |-{QThread},524
  |   `-{CpuMemState},525
  |-systemd-udevd,420
  |-haveged,423 --Foreground --verbose=1 -w 1024
  |-systemd-journal,425
  |-qaxtray_5,518 --reboot
  |   |-{QXcbEventReader},523
  |   |-{llvmpipe-0},526
  |   |-{llvmpipe-1},527
  |   |-{llvmpipe-2},528
  |   |-{llvmpipe-3},529
  |   |-{QDBusConnection},530
  |   |-{gmain},531
  |   |-{gdbus},532
  |   |-{qaxtray_5},581
  |   |-{qaxtray_5},582
  |   |-{qaxtray_5},583
  |   |-{qaxtray_5},584
  |   |-{QThread},591
--更多--

3.3 pstree -p 795：显示以PID为795的进程为根的进程树，包括PID

[purpleendurer @ bash ~] pstree -p 795
accounts-daemon(795)─┬─{gdbus}(834)
                     └─{gmain}(824)
[purpleendurer @ bash ~]