linux fork dup dup2 coding - JohnHau/mis GitHub Wiki
https://www.unix.com/programming/17522-understanding-purpose-dup-dup2.html
https://www.geeksforgeeks.org/dup-dup2-linux-system-call/
https://www.cems.uwe.ac.uk/~irjohnso/coursenotes/lrc/system/ipc/ipc3.htm https://localcoder.org/c-dup2-pipe-and-fork-not-working-as-expected
https://man7.org/linux/man-pages/man2/dup.2.html https://www.796t.com/p/1381563.html
https://webdocs.cs.ualberta.ca/~tony/C379/C379Labs/Lab2/exec.html http://www.cs.toronto.edu/~maclean/csc209/Fall98/Slides/Week8/tsld007.htm
https://cs61.seas.harvard.edu/site/2019/ShellEx/
https://www.gnu.org/software/libc/manual/html_node/Duplicating-Descriptors.html
https://softwarebrother.com/entry/dup2+fork.html
https://www.ibm.com/docs/en/aix/7.1?topic=volumes-using-file-descriptors
https://blog.birost.com/a?ID=00250-4473e104-d9d5-48df-b7bf-be97b41a0e54 https://quick-adviser.com/what-is-the-use-of-dup-system-call/
http://www.cppblog.com/aaxron/archive/2012/08/09/186738.html
https://codeantenna.com/a/OyX4Do9A2c
https://tousu.in/qa/?qa=695054/
https://docs.oracle.com/cd/E23824_01/html/821-1463/dup-2.html
https://jike.in/qa/?qa=695054/
https://www.qnx.com/developers/docs/7.1/#com.qnx.doc.neutrino.lib_ref/topic/d/dup2.html
https://people.cs.rutgers.edu/~pxk/416/notes/c-tutorials/dup2.html
https://www.cnblogs.com/crafet/tag/dup%20dup2%20fork%20execlp/
https://blog.csdn.net/weixin_38932035/article/details/105286118
https://www.cs.princeton.edu/courses/archive/fall04/cos217/lectures/21pipes.pdf
https://www.cnblogs.com/Hxinguan/p/5007393.html
https://www.mkssoftware.com/docs/man3/dup2.3.asp
https://blog.birost.com/a?ID=01650-bf1e42ec-3a2e-4a42-93b4-cc88cdcd74d6
https://blog.actorsfit.com/a?ID=01000-558283a9-1964-4908-b2ef-1a9069cbdc52
https://www.ibm.com/docs/en/zos/2.3.0?topic=functions-dup2-duplicate-open-file-descriptor-another
https://github.com/skuhl/sys-prog-examples/blob/master/simple-examples/pipe-dup2.c
https://inst.eecs.berkeley.edu/~cs162/fa20/static/sections/section3.pdf
https://www.usna.edu/Users/cs/bilzor/ic221/calendar.php?type=class&event=16
https://quick-adviser.com/what-is-dup2-in-pipe/
https://sites.cs.ucsb.edu/~rich/class/cs170/labs/kos_pipe/heloise.html
https://linuxhint.com/dup2_system_call_c/
https://fullstackuser.com/questions/489762/can-someone-explain-what-dup-in-c-does
https://cse.buffalo.edu/~bina/cse321/fall2016/Lectures/Nov4Pipes.html
https://codegrepr.com/question/dup2-dup-why-would-i-need-to-duplicate-a-file-descriptor/
https://courses.cs.duke.edu/spring16/cps110/slides/unix-io.pdf
https://www.tutorialspoint.com/unix_system_calls/dup.htm
https://www.programmerall.com/article/44121129565/
https://docs.microsoft.com/en-us/cpp/c-runtime-library/reference/pipe?view=msvc-170 http://igm.univ-mlv.fr/ens/Licence/L3/2016-2017/System/td05.php
http://www-scf.usc.edu/~alfarrar/courses/CS415_Sp2020/slides/Lecture6.pdf
https://linux.die.net/man/2/dup2
http://manpages.ubuntu.com/manpages/trusty/man2/dup2.2freebsd.html
https://qa.icopy.site/questions/29858707/confusion-with-dup2-exec-and-pipes
https://www.c-plusplus.net/forum/topic/146978/pipe-fork-exec-und-dup-dup2-programmieren-einer-shell
https://www.coder.work/article/2130726
https://blog.51cto.com/jiangjqian/407921
http://didawiki.cli.di.unipi.it/lib/exe/fetch.php/lcs/lcs06/esercitazioni/09pipe.pdf
http://unixwiz.net/techtips/remap-pipe-fds.html
https://karatos.com/art?id=55328bd1-6d21-45fd-a727-4ad34c25c0c0
https://docwiki.embarcadero.com/RADStudio/Sydney/en/Pipe
http://www.cs.kent.edu/~ruttan/sysprog/lectures/pipes.pdf
http://www.csc.villanova.edu/~mprobson/courses/sp22-csc2405/slides/3.2-Pipes.pdf
http://odl.sysworks.biz/disk$axpdocdec971/progtool/deccv56/5763profile0133.html
https://www.programmersought.net/article/332017036.html
https://www.daimajiaoliu.com/daima/46abf2ffa9003f0
https://cpp.hotexamples.com/examples/-/-/dup2/cpp-dup2-function-examples.html
https://linuxfr.org/forums/programmation-c--2/posts/communication-entre-processus-avec-pipe-et-dup2
https://stringfixer.com/ar/Dup2
http://danzig.jct.ac.il/unix_class/Lab3.html
https://www.linuxquestions.org/questions/programming-9/dup-and-dup2-useful-593303/
https://firstlawcomic.com/what-does-dup-mean-in-c/
https://sites.ualberta.ca/dept/chemeng/AIX-43/share/man/info/C/a_doc_lib/libs/basetrf1/fcntl.htm
https://cboard.cprogramming.com/c-programming/87387-[c]-pipe-hangs.html
https://qastack.it/programming/11635219/dup2-dup-why-would-i-need-to-duplicate-a-file-descriptor
https://www.codeleading.com/article/2594869644/
https://it-qa.com/what-does-dup-and-dup2-do/
https://cs3210.cc.gatech.edu/l/lec03.pdf
https://askcodez.com/pipes-dup2-et-exec.html
https://www.cs.virginia.edu/~cr4bd/4414/S2021/slides/20210216-slides.pdf
https://www.classes.cs.uchicago.edu/archive/2016/winter/51081-1/labs/LAB5/lab5.html
https://www.codetd.com/article/11937535
https://www.forosdeinformatica.com/index.php?topic=14968.10;wap2
https://arstechnica.com/civis/viewtopic.php?f=20&t=549932
https://www.twblogs.net/a/5cc4b58dbd9eee39711464b7
https://flylib.com/books/en/1.23.1/unnamed_pipes.html
https://microeducate.tech/tag/dup2/
http://blog.chinaunix.net/uid-97185-id-4330836.html
https://ocaml.github.io/ocamlunix/pipes.html
http://computer-programming-forum.com/32-perl/e7dfcfc6bbc946b4.htm
https://i.cs.hku.hk/~fcmlau/POS/lectures/17.html
http://www.ipnom.com/FreeBSD-Man-Pages/dup2.2.html
https://forums.opensuse.org/showthread.php/464144-problems-with-the-std-pipes