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 contextsPID 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1 |
| USER | 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 ~]
