20201127 use markdown to draw UML diagrams, graphviz installation experience hematemesis finishing

1 visio code Editor , It's better to have
2 visio code markdownlint Plug in installation , This plug-in can compare visio code Self contained markdown Preview shows better .
This tool is for preview
3 markdown Can support plantuml Language to draw all kinds of pictures . also markdownlint The plug-in can preview some of the pictures it forms . however , Just a very simple preview . For example, class diagrams and other complex , It will fail to preview . So your computer needs to install another image related tool —Graphviz Installation of this guy , I encountered a huge pit in the whole process ！

4 Usually Graphviz Installation , Just a simple command , （ But obviously, what I experienced is not here “ Usually ” situation ！）

• brew install graphviz
  It's ready to install , But this order alone , Ah , It 's a long story .
  1 First of all, yours. mac There has to be this Homebrew Tools , otherwise , Computers are not human You this brew What does a word mean , Not to mention letting him execute later install Instructions . Without this tool , use Baidu Search Homebrew Installation tutorial , There's a lot inside , In my impression , This should not encounter much difficulty . When I installed my new notebook, I found a particularly useful post https://blog.csdn.net/yuanshangshenghuo/article/details/106599836
  2 It happens that my computer has been installed , So you can enter the command directly ,, After secretly happy , Happy copy command , I thought it would be ...
  3 But ah , This is the beginning of a nightmare .........
  • First , After I typed the order , There appears in the terminal Update homebrew… Relevant words .（ I can't remember whether the word is this , Always update brew Tool means ）. Just a little more , What's the big deal . however , Such an order has been terminal There is a pestle in the tool ,, There is no further printing ！ what？？
  • I can't do anything without thinking , I tried this many times , That's how it came about , This is a brew Automatic update . I have an idea , What I need now is to install it Graphviz That's it , No more updates HomeBrew It doesn't matter ！ So I want to , Is there any way to make brew Do not update the version , Download directly .
  • So I Baidu , stop it brew Auto update . Xi xi xi , I found the answer immediately ！ namely ： Open environment variable configuration file , Edit it , Add a word like this ：export HOMEBREW_NO_AUTO_UPDATE=true
  • 
    The whole input process ：
    - use vim Open the environment profile ： sudo vim ~/.bash_profile ( Ha ha ha , So here comes the question , The file is open , But it's useless for a long time vim Of me , hold vim I forgot some operation instructions of ！！！)
    - So I turned to vim How to edit , How to finish editing , How to quit （ To this extent , I hate myself ）
    - Then I found the answer ： Hold down i key , Get into vim Edit mode , Then put that sentence , Copy and paste in , Then press and hold esc Key to exit edit mode . Then press the colon with your hand “:” key , Input wq, Represents writing to a file and exiting vim. After an operation , I quit to the original terminal Interface , I feel finished . Finally, you can not update automatically, hee hee ！ So enter again brew install graphviz, I feel like I'm about to see the dawn ！！ Looking forward to the next step .
    - Then it appears on the screen Update homebrew… It's collapsing ！！！what situation ！！
    - Lament again , Why am I so frustrated in everything ！！ Ah ！ I had a look , Only then discovered , Although I changed the environment variable , however , I didn't make it work ！！ The order in effect is simple , Input ： source .bash_profile Can finish . This is definitely a low-level pit , Think of my precious time being wasted , Don't give up in your heart ！ I remember right , This is the second time I have made such a mistake ！ Too much .
    - good , In this way, I really put an end to brew The problem of automatic update ！ Then continue with the previous brew install graphviz Instructions , Ran goose , There is a problem again ！ Prompt me on the console ： It's said that we can't find a way , Something went wrong ！！！！ My patience is running out .
    - So I Baidu , The answer is , to update brew edition ！！！！ Ah ah ah ,, I have worked hard to block brew What is the meaning of automatic update ？
    - So I turned around and updated brew Go to ,, Input the command to start the New Nightmare mode ： brew update -v ( Instructions from Baidu ) -_-|| , then ,,,terminal There has been no content update , Don't move ！！！！
    - So the problem goes back to the beginning , and Update homebrew… Stuck is basically the same problem .. I have to solve this , Specific goals , brew Must update , So I can install Graphviz Tools , And then use markdown Write all kinds of pictures ！
    - So I found a solution with Baidu , I found many web pages , Try various commands during , The pit has been trampled for almost a day ,( I'm not very clear about the concept of mirror image , The Internet says to change the image , Also posted a variety of mirror addresses , But you tell me clearly , How to change , Which modules to change , How to change it ！ What I want is not only the address , And all the replacement instructions ！！！) Spit blood to find a suitable post to solve this problem ：mac Use brew update The solution of slow update without response This is very clear , I copied it according to the following figure ：
    
    
    Copy line by line .
• good , I replaced the source , It's not far from a successful update , So I input again brew update -v Instructions , Ha ha ha , Not stuck all the time , It seems to be different from the original , But it didn't go well , Wrong again. ！
• 
  My patience was worn away , So I don't want to care about anything , But I really want to see the current brew Version number of , Find out , The version number has been updated , Although an error was reported during the update ！！ Unexpected joy ！！ So I thought it had been updated , If later because of this Error Affect something , That's all for the future , Maybe I won't meet it .

A friend recommended a post , There are simpler commands that can replace the above scheme Please click

• good , At present, it is difficult to install Graphviz . Execution instruction ： brew install graphviz （ ok , At this time, I was about to burst into tears , Too much suffering ）
• Then came some pits .... Frustration ！！！！
• The first alarm ：
  But this tip is still very friendly ！ At least the editor told you , Let you carry out xcode-select --install Instructions ！！！ Fortunately, my computer has xcode,, Otherwise I'm really going to collapse , So I executed this prompt instruction again , Then the computer pops up , I just click , download , became , This problem is solved ！
• Then I execute again brew install graphviz Instructions , Anyway, this task doesn't start from scratch every time , He will check the completed documents . Then I came across another problem ：
• 
  See the dawn , How to give up easily ！！！ use Baidu Search ！！ Find out , This is a general problem ！ And change the configuration file , This one came across , Suggest Baidu , This is a very common question , Good operation ！
• Solved this , Carry on brew install graphviz , During this period, many problems occurred , however , At this time, you must read carefully termianl Printing of ！！！ Its printing is no longer the same as the previous printing , It's confusing , feel at a loss , Only Baidu , Next print , It's to tell you , What instructions are you going to execute , Change the corresponding environment variables , Follow the instructions step by step ！ for example ：
• 
  - Here I admit , I didn't put all the hints , All changed , But it's so inexplicable , Installation is successful ！
• Until the last time I input brew install graphviz Gave the following print ：
• 
  （....................）
  Tears of joy ！！！！！！！！！！！！！！！！！！！！！！

5 Restart now visio code Look at the changes ：

It's hard to calm down ,
Open it quickly plantuml grammar link , Learn how to draw all kinds of pictures ！