Meaning of "```bash"
 

Somewhere I saw the commands

```bash
luarocks install cudnn
```
when type the first command it show prompt
>>
second one the same
>>
third one it get back to normal prompt

ls shows no files
need to type exit,
then there are some message and ls shows files

what is the meaning of ```bash?
and what state it entered?

Thanks

There is no "meaning", it is for stylistical purpose in the markdown language. What you have seen is part of a markdown file: https://github.com/jcjohnson/denseca...54fe03d90eb201

That markdown (.md) file looks like this with formatting:
https://github.com/jcjohnson/densecap

So, ``` "means" syntax highligting in markdown.

Read more here:
https://guides.github.com/features/mastering-markdown/

Wordpress for example, is notorious for screwing up, I mean Marking Up "--"

Thanks
It is README.md file, did not know what md stands for. So in xterminal no need to enter first and third commands?

In the future, instead of saying "Somewhere I saw the commands", which in of it self is useless information, had you of said, "I was reading a README.md file and saw the following:", people reading
your question would know instantly what you are talking about.

You're right... Fortunately HMW knew instantly what he was writing about ;).

I came here because I saw
```bash
cd /path/to/the/project
php init_db.php
```

and I wondered what do they mean by ``` ?

Yes, I was in a README.md but I would not have known that that had any bearing on the question. If I had known there was a relation I wouldn't have had the question. Just saying ;)

> and I wondered what do they mean by ``` ?

It means "be prepared, the code starts in the next line"

https://daringfireball.net/projects/markdown/syntax

(Woops, sorry, didn't saw the earlier answers...)