软件包安装
1. 打印进程树pstree
安装psmisc，
apt-get install psmisc
psmisc（process miscellaneous）包含使用proc文件系统的一些小工具。
- fuser - Identifies processes using files or sockets
- killall - kills processes by name, e.g. killall -HUP named
- prtstat - prints statistics of a process
- pslog - prints log path(s) of a process
- pstree - shows the currently running processes as a tree
- peekfd - shows the data travelling over a file descriptor
（1）proc文件系统
proc文件系统是一种伪文件系统（虚拟文件系统），存储的是当前内核运行状态的一系列特殊文件，可以通过这些文件查看有关系统硬件及当前正在运行进程的信息，甚至可以通过更改其中某些文件来改变内核的运行状态。
# ls -a /proc
. 1791286 1958390 2005145 2009536 2016481 2022886 2038562 2052154 2058771 2069014 264 39986 66 900 ioports
.. 1791334 1959014 2005148 2009596 2016549 2023110 2038644 2052414 2058780 2069165 27 39987 666 901 irq
1 1793199 1961 2005230 2009599 2016554 2025538 2038645 2052512 2058864 2069167 28 39988 68 904 kallsyms
10 1793276 1978221 2005231 2009679 2016636 2025604 2038694 2052515 2059031 2069253 283 39989 68477 91 kcore
1000 1794746 1979828 2005390 2009680 2016641 2025716 2038733 2052576 2059038 2069254 284 39990 69 912056 keys
1011093 1795994 1992311 2005431 2010225 2016658 2025718 2038742 2052578 2059391 2069337 285 39991 70 912057 key-users
1011096 1796285 1992602 2005434 2010277 2016752 2025805 2038770 2052679 2059398 2069461 286 39992 71 912058 kmsg
108408 1796354 1992603 2005514 2010288 2016755 2025806 2038799 2052680 2059764 2069464 2864954 4 72 912590 kpagecgroup
108410 1797439 2 2005515 2010289 2016835 2026153 2038800 2052913 2059774 2069835 287 40 74 912591 kpagecount
108416 1797502 20 2005812 2010367 2016836 2026158 2038826 2052991 2060501 2069846 2874 41 75 912592 kpageflags
108634 1798795 2002782 2005884 2010368 2016959 2026180 2038886 2053123 2060786 2070373 288 413 757 912917 loadavg
11 1798797 2002814 2006036 2011561 2016961 2026251 2038887 2053182 2060788 2070384 289 42 757366 912918 locks
1119840 1798928 2002940 2006037 2012653 2017043 2026252 2040217 2053186 2060807 2070899 29 4225 758 912919 mdstat
1151889 1798944 2002952 2006114 2012764 2017049 2027424 2040302 2053264 2060884 2070932 290 424 759 914782 meminfo
1151892 1799414 2003036 2006115 2012765 2017709 2027748 2040305 2053265 2060885 2070941 291 425 76 914783 misc
1152869 1799759 2003055 2006228 2012828 2017755 2027751 2040388 2054089 2061338 2070956 292 436696 760 914784 modules
12 18 2003089 2006230 2012836 2017766 2028438 2040389 2054202 2061349 2070957 293 44 77 916994 mounts
13 180 2003091 2006314 2012942 2017804 2028554 2040452 2054205 2061403 2070999 294 45 78 916995 mtrr
138 1801809 2003174 2006317 2012943 2017865 2028560 2040778 2054225 2061411 2071000 3 46 782 916996 net
139 1802241 2003175 2007163 2012951 2018012 2028564 2040792 2054283 2061419 2071001 30 47 783 919946 pagetypeinfo
14 1802863 2003648 2007312 2012952 2018013 2028648 2041040 2054286 2061670 2071083 318 48 785 919947 partitions
140 1803729 2003650 2007314 2013036 2018208 2028653 2041047 2054523 2061673 2071090 32 50 788 919948 pressure
1406376 1803896 2003723 2007398 2013037 2018209 2031906 2045510 2054537 2061751 2071092 329 51 789 921016 sched_debug
143 1804498 2003726 2007399 2013208 2018297 2031919 2045565 2054624 2061752 2071093 33 52 792 928 schedstat
144 1806132 2003806 2007446 2013330 2018298 2032713 2045567 2054626 2062413 2071098 336 525 794 931 scsi
145 1806235 2003807 2008113 2013333 2018401 2032940 2045664 2054688 2062556 2071099 34 528 797 960 self
146 1806238 2003822 2008224 2013430 2018485 2032945 2045667 2054692 2062572 21 342 53 80 acpi slabinfo
147 1806240 2003824 2008225 2013582 2018488 2033322 2046120 2055061 2062947 22 35 533 81 asound softirqs
148 1827440 2003904 2008305 2013589 2018513 2033337 2046390 2055195 2062964 2253091 355 54 82 buddyinfo stat
15 1827501 2003905 2008306 2013693 2018574 2035624 2046516 2055199 2063418 2255266 36 554131 83 bus swaps
151 1885261 2004035 2008706 2013774 2018577 2036915 2046517 2055284 2063704 2255267 370 554219 84 cgroups sys
152 1885348 2004043 2008731 2013777 2018621 2036925 2046547 2055308 2064086 2259266 37801 555639 86 cmdline sysrq-trigger
154 1885349 2004086 2008734 2013864 2018622 2037744 2046625 2055348 2064087 2260001 37809 555962 868 consoles sysvipc
155 1885351 2004088 2008813 2013867 2018705 2037757 2046628 2055599 2065899 2260136 37911 56 87 cpuinfo thread-self
156 1885396 2004905 2008814 2014238 2018706 2037759 2046827 2056236 2065906 2260146 38 561842 870485 crypto timer_list
157 1885406 2004915 2008892 2014306 2018753 2037798 2046830 2056310 2067071 2262804 39 57 870487 devices tty
16 1885436 2004918 2008930 2014309 2018824 2037863 2047204 2056321 2067105 2297191 39968 576 871 diskstats uptime
165 1885458 2005000 2008931 2014394 2018825 2037873 2047422 2057020 2067118 2297194 39970 58 873 dma version
166 1885469 2005001 2009015 2014397 2018912 2038196 2048646 2057032 2067316 2297617 39979 59 88 driver version_signature
168 1885519 2005007 2009016 2014713 2018913 2038250 2048767 2057244 2067319 23 39980 6 882 execdomains vmallocinfo
17 1940003 2005012 2009106 2014715 2018983 2038252 2048768 2057749 2067772 24 39981 60 883 fb vmstat
177 195 2005023 2009241 2014800 2020004 2038351 2048850 2057756 2068060 254 39982 62 89 filesystems zoneinfo
1779500 1950060 2005025 2009243 2014801 2020012 2038356 2048851 2058292 2068073 258 39983 63 897 fs
1790169 1950062 2005105 2009323 2014876 2020643 2038531 2049736 2058424 2068571 259 39984 64 9 interrupts
1790171 1950766 2005106 2009324 2016409 2020651 2038561 2052133 2058425 2068583 26 39985 65 90 iomem
它里面包含了很多小工具用于管理Linux系统进程，pstree只是其中之一：
- fuser – 使用文件或套接字识别进程
- killall – 结束给定名称的进程
- prtstat – 输出进程的统计信息
- pslog – 输出进程日志路径
- pstree – 以树状形式显示当前运行的进程
- peekfd – 显示通过文件描述符传输的数据