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Input and Output #20

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2 changes: 1 addition & 1 deletion lessons/ar/chapter_10.yaml → lessons/ar/chapter_11.yaml
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- title: الفصل 10 - النهاية
- title: الفصل 11 - النهاية
content_markdown: >
لقد كان من دواعي سروري أن نكون معك في دورة تعلم رست (Rust). فيريس (Ferris) وفريق دورة تعلم رست (the Tour of Rust team) يأملون جدا بأن تستمتع برحلتك المقبلة في تعلم رست (Rust)! إذا شعرت بالإرتياح لما تعلمت حتى الآن، فإننا نوصيك بالتعمق أكثر في اللغة من خلال هذه الموارد:

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2 changes: 1 addition & 1 deletion lessons/de/chapter_10.yaml → lessons/de/chapter_11.yaml
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- title: Kapitel 10 - Das Ende
- title: Kapitel 11 - Das Ende
content_markdown: >
Es war eine Freude, dich bei der Tour durch Rust dabei gehabt zu haben.
Ferris und das ,,Tour of Rust"-Team hoffen, dass es dir gefallen hat!
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153 changes: 146 additions & 7 deletions lessons/en/chapter_10.yaml
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- title: Chapter 10 - The End
- title: Chapter 10 - I/O
content_markdown: >
It's been a joy to have you on the Tour of Rust. Ferris and the Tour of Rust
team sincerely hope you enjoy the journey ahead! If you
In computing, `I/O` is an abbreviation for `Input/Output` operation.

The `input` is what the computer and the algorithm receive and
the `output` represents the result generated based on the `input`.

Thing about `I/O` as a stream of information
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A compute system without output is nearly useless.

It will always run the same code on the same data and, thus, produce the same result.

have felt comfortable this far, we strongly recommend diving deeper with
these resources:
- title: Do it locally
content_markdown: >
In this chapter, the Playground will be just a code support for you :(.

Since most of the `I/O` programs are designed to compile on a local machine
(yours :) ), consider setting up a Rust environment on your personal computer and
familiarise yourself with the terminal.

Also, consider using an `IDE`, such as `VS Code` or `RustRover`
and familiarise yourself with the [terminal](https://www.youtube.com/watch?v=lZ7Kix9bjPI).

- title: Standard Input (stdin)
content_markdown: >
`Standard Input` refers to the data provided by the user for the algorithm to process.


Thus, the `input` represents what a program is being given.
Mostly, in terms of `input`, you'll work with `String` and `files`.


The Rust library `std::io` has the necessary components to interact with `I/O`
channels, such as the keyboard or any other input source.
code: >-
https://play.rust-lang.org/?version=stable&mode=debug&edition=2018&code=use+std%3A%3Aio%3B%0A%0Afn+main%28%29+%7B%0A++++let+mut+input+%3D+String%3A%3Anew%28%29%3B%0A%0A++++%2F%2F+the+read+will+be+stopped+by+%60%5Cn%60+character%0A++++if+let+Ok%28_%29+%3D+io%3A%3Astdin%28%29.read_line%28%26mut+input%29+%7B%0A++++++++println%21%28%22Input+text+%3A+%7B%7D%22%2C+input%29%3B%0A++++%7D%0A%7D%0A

- title: Standard Output (stdout)
content_markdown: >
Remember the first lesson? Can you notice something relevant to `I/O`?

Of course that what `println!` does is an output operation,
in fact it directs (outputs) text to `stdout` (stdout)
and it will be displayed on the screen.

If you don't want to print a new line character `\n` for you, use `print!`
code: >-
https://play.rust-lang.org/?version=stable&mode=debug&edition=2018&code=use+std%3A%3Aio%3B%0A%0Afn+main%28%29+%7B%0A++++let+mut+input+%3D+String%3A%3Anew%28%29%3B%0A%0A++++%2F%2F+the+read+will+be+stopped+by+%60%5Cn%60+character%0A++++if+let+Ok%28_%29+%3D+io%3A%3Astdin%28%29.read_line%28%26mut+input%29+%7B%0A++++++++println%21%28%22Input+text+%3A+%7B%7D%22%2C+input%29%3B%0A++++%7D%0A%7D%0A

- title: Standard Error (stdout)
content_markdown: >
In order to separate error reporting from common printing, you can use the `eprint!` and
`eprintln!` macros that will display text in the standard error (`stderr`) channel,
instead of `stdout`. Use this macro with an informative message.

In UNIX-like systems, such as macOS or LINUX, you can separate the two types of
output by using redirections:
- `./main > output.txt`
- `./main >> output.txt`
- `./main 2> output.txt`
- `./main 2>> output.txt`


> The commands with `2` will copy only the errors generated by the program, and the ones without `2` will discards all errors.

> The command with `>>` will add text at the end of the file, while the operator `>` will override the file.
code: >-
https://play.rust-lang.org/?version=stable&mode=debug&edition=2018&code=use+std%3A%3Aio%3B%0A%0Afn+main%28%29+%7B%0A++++let+mut+input+%3D+String%3A%3Anew%28%29%3B%0A%0A++++%2F%2F+the+read+will+be+stopped+by+%60%5Cn%60+character%0A++++if+let+Ok%28_%29+%3D+io%3A%3Astdin%28%29.read_line%28%26mut+input%29+%7B%0A++++++++println%21%28%22Input+text+%3A+%7B%7D%22%2C+input%29%3B%0A++++%7D%0A%7D%0A

- title: File Descriptors
content_markdown: >
Now that we know what are the basic `I/O` operations, we dive even deeper.

You've already seen before: `stdin` (standard input), `stdout` (standard output) and `stderr` (standard error).
For each of them it is associated a positive integer number, a unique identifier
for an `I/O` channel (example: file), known as a `file descriptor (fd)`.

* [The Official Rust Programming
Book](https://doc.rust-lang.org/stable/book/)
Therefore:
- `stdin`: 0
- `stdout`: 1
- `stderr`: 2
- files

[![file descriptors](https://cs-pub-ro.github.io/operating-systems/assets/images/file-descriptors-d19424f0a417ecd1c032f98a1969ad75.svg)


Working with files plays an important role in the `I/O` operations.

You've already learned to open a text file and read its content.

But how about writing data in it, as an `I/O` channel.
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code: >-
https://play.rust-lang.org/?version=stable&mode=debug&edition=2018&code=use+std%3A%3Afs%3A%3A%7Bself%2C+File%7D%3B++++++%2F%2F+file+system%0Ause+std%3A%3Aio%3A%3A%7Bself%2C+Write%7D%3B+++++%2F%2F+input+output%0A%0Afn+main%28%29+-%3E+io%3A%3AResult%3C%28%29%3E+%7B%0A++++let+file_name+%3D+%22output.txt%22%3B%0A%0A++++%2F%2F+creates+the+file+if+it+doesn%27t+already+exists%0A++++let+mut+file+%3D+File%3A%3Acreate%28file_name%29%3F%3B%0A%0A++++let+text_to_write+%3D+%22Hello%2C+World%21%5Cn%5C%0A++++++++++++++++++++++++++++This+is+a+line+of+text.%5Cn%22%3B%0A++++file.write_all%28text_to_write.as_bytes%28%29%29%3F%3B%0A%0A++++let+absolute_path+%3D+fs%3A%3Acanonicalize%28file_name%29%3F%3B%0A++++println%21%28%22Text+has+been+written+to%3A+%7B%3A%3F%7D%22%2C+absolute_path%29%3B%0A%0A++++return+Ok%28%28%29%29%3B%0A%7D%0A

- title: System Arguments
content_markdown: >
A Rust program is able to receive `input` from the in-line arguments.

In order to do so, open a [terminal](https://www.youtube.com/watch?v=lZ7Kix9bjPI), compile it and pass the arguments to the executable in the command promt.
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These arguments might be relevant files, flags and so on.
The developer must document their purpose.

If you are using LINUX or macOS, bear in mind these commands:
```bash
$ touch main.rs
$ rustc main.rs
$ ./main.rs 2 3 4 5
```

Otherwise, for Windows environment, on a PowerShell and paste them
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```PowerShell
> echo. > main.rs
> rustc main.rs
> .\main.exe 2 3 4 5
```


> Notice that the first argument is the executable itself

code: >-
https://play.rust-lang.org/?version=stable&mode=debug&edition=2018&code=use+std%3A%3Aenv%3B+++++++%2F%2F+env+stands+for+environment%0A%0Afn+main%28%29+%7B%0A++++let+args%3A+Vec%3CString%3E+%3D+env%3A%3Aargs%28%29.collect%28%29%3B%0A++++println%21%28%22number+of+arguments+%3D+%7B%7D%22%2C+args.len%28%29%29%3B%0A++++println%21%28%22the+inline+arguments+are+%3A+%7B%3A%3F%7D%22%2C+args%29%3B%0A%7D%0A

- title: Environment Variables
content_markdown: >
You've seen that the Rust standard library grants access to the system.

Using the `std::env` module, you can do in Rust some task that might require
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a UNIX terminal, such as:
- command line arguments
- printing the current working directory
- current executable path
- working with environmental variables
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- working with files and directories

code: >-
https://play.rust-lang.org/?version=stable&mode=debug&edition=2018&code=use+std%3A%3Aenv%3B+++%2F%2F+for+interacting+with+the+system%27s+environment%0A%0Afn+main%28%29+%7B%0A%0A++++if+let+Ok%28current_dir%29+%3D+env%3A%3Acurrent_dir%28%29+%7B%0A++++++++if+let+Some%28pwd%29+%3D+current_dir.to_str%28%29+%7B%0A++++++++++++println%21%28%22The+current+working+directory+%3D+%7B%7D%22%2C+pwd%29%3B%0A++++++++%7D%0A++++%7D%0A%0A++++%2F%2F+%24+echo+%24PWD++++++%23+environment+variable%0A++++%2F%2F+if+you+don%27t+want+to+see+Seme%28...%29%2C+you+have+to+pattern+match+on+Ok%28%29%0A++++println%21%28%22The+current+working+directory+%3D+%7B%3A%3F%7D%22%2C+env%3A%3Avar%28%22PWD%22%29.ok%28%29%29%3B%0A%0A++++%2F%2F+%24+echo+%24PWD++++++%23+environment+variable%0A++++if+let+Ok%28pwd%29+%3D+env%3A%3Avar%28%22PWD%22%29+%7B%0A++++++++println%21%28%22The+current+working+directory+%3D+%7B%7D%22%2C+pwd%29%3B%0A++++%7D%0A%0A++++%2F%2F+%24+echo+%24USER+++++%23+environment+variable%0A++++if+let+Ok%28user%29+%3D+env%3A%3Avar%28%22USER%22%29+%7B%0A++++++++println%21%28%22The+current+user+is%3A+%7B%7D%22%2C+user%29%3B%0A++++%7D%0A%0A%0A++++%2F%2F+%24+echo+%24IDK++++++%23+I+suppose+you+didn%27t+set+this+variable+%3A%29%0A++++if+let+Err%28err%29+%3D+env%3A%3Avar%28%22IDK%22%29+%7B%0A++++++++eprintln%21%28%22IDK+%3A+%7B%7D%22%2C+err%29%3B%0A++++++++env%3A%3Aset_var%28%22IDK%22%2C+%22%3D+I+don%27t+know%22%29%3B%0A++++++++println%21%28%22IDK+%3D+%7B%3A%3F%7D%22%2C+env%3A%3Avar%28%22IDK%22%29.ok%28%29%29%3B%0A++++++++env%3A%3Aremove_var%28%22IDK%22%29%3B%0A++++%7D%0A%7D%0A
- title: Chapter 10 - Conclusion
content_markdown: >
Now that you know the basic of Input/Output operations, you used just two
Rust libraries along the way, and they are standard, by the way: `std::env` and `std::fs`.

Now, you can build your own file managing system, Web App or even API.

Checkout these resources:
- [Environment Variables](https://youtu.be/npsMN-tZNVs)
- [Rust API](https://youtu.be/_ccDqRTx-JU)

9 changes: 9 additions & 0 deletions lessons/en/chapter_11.yaml
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- title: Chapter 11 - The End
content_markdown: >
It's been a joy to have you on the Tour of Rust. Ferris and the Tour of Rust
team sincerely hope you enjoy the journey ahead! If you

have felt comfortable this far, we strongly recommend diving deeper with
these resources:

* [The Official Rust Programming Book](https://doc.rust-lang.org/stable/book/)
2 changes: 1 addition & 1 deletion lessons/en/chapter_4.yaml
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function called `unwrap` that can be useful for getting a value in a quick
and dirty manner. `unwrap` will:

1. Get the value inside Option/Result

2. If the enum is of type None/Err, `panic!`
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2 changes: 1 addition & 1 deletion lessons/en/chapter_9.yaml
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content_markdown: >
Rust has several keywords you can use in your `use` path to quickly get
ahold of the module you want:

* `crate` - the root module of your crate

* `super` - the parent module of your current module
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2 changes: 1 addition & 1 deletion lessons/es/chapter_10.yaml → lessons/es/chapter_11.yaml
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- title: Capítulo 10 - Fin
- title: Capítulo 11 - Fin
content_markdown: >
Esto es todo por ahora, pero aún quedan más capítulos, así que ¡muy atento!
Esperamos que disfrutes del viaje.
2 changes: 1 addition & 1 deletion lessons/fa/chapter_10.yaml → lessons/fa/chapter_11.yaml
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- title: Chapter 10 - The End
- title: Chapter 11 - The End
content_markdown: >
It's been a joy to have you on the Tour of Rust. Ferris and the Tour of Rust
team sincerely hope you enjoy the journey ahead! If you
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2 changes: 1 addition & 1 deletion lessons/fr/chapter_10.yaml → lessons/fr/chapter_11.yaml
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- title: Chapitre 10 - Fin
- title: Chapitre 11 - Fin
content_markdown: >
Ce fut une joie de t'avoir sur le Tour de Rust. Ferris et l'équipe du

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2 changes: 1 addition & 1 deletion lessons/gr/chapter_10.yaml → lessons/gr/chapter_11.yaml
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- title: Κεφάλαιο 10 - Το Τέλος
- title: Κεφάλαιο 11 - Το Τέλος
content_markdown: >
Μεγάλη μας χαρά που σας είχαμε στην Ξενάγηση στη Rust. Ο Ferris και η ομάδα της Ξενάγησης ελπίζουμε ειλικρινά να απολαύσετε το ταξίδι που σας περιμένει! Αν αισθάνεστε άνετα ως τώρα, προτείνουμε ανεπιφύλακτα να διεισδύσετε πιο βαθιά με τα εξής βοηθήματα:

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2 changes: 1 addition & 1 deletion lessons/hu/chapter_10.yaml → lessons/hu/chapter_11.yaml
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- title: 10. Fejezet - Vége
- title: 11. Fejezet - Vége
content_markdown: |
Örülök, hogy velem tartottál a Rust-túrán! Ferris és a Rust-túra csapata őszintén reméli, hogy
tetszeni fog, ami utad során rád vár! Ha az eddigieket kényelmesnek találtad, melegen ajánljuk
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2 changes: 1 addition & 1 deletion lessons/ie/chapter_10.yaml → lessons/ie/chapter_11.yaml
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- title: Capitul 10 - Fine
- title: Capitul 11 - Fine
content_markdown: >
To es omnicos por nu. Plu tard va venir nov contenete. Yo espera que tu va
juir li viage a sequer!
2 changes: 1 addition & 1 deletion lessons/ja/chapter_10.yaml → lessons/ja/chapter_11.yaml
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- title: 第 10 章 - 終わりに
- title: 第 11 章 - 終わりに
content_markdown: "Rustツアーに参加していただきありがとうございました。フェリスとRustツアーチームは皆さんが今後も楽しんでくれるよう願っています。\t\nここまで楽しんでいただけたなら、以下の資料を通してより深く学ぶのを推奨します。\t\n* [The Official Rust Programming Book](https://doc.rust-lang.org/stable/book/)\n"
2 changes: 1 addition & 1 deletion lessons/ko/chapter_10.yaml → lessons/ko/chapter_11.yaml
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- title: 10장 - 끝
- title: 11장 - 끝
content_markdown: >
Tour of Rust를 함께 해서 즐거웠습니다. Ferris와 Tour of Rust 팀은
여러분이 앞에 놓인 여정을 즐기시길 진심으로 바랍니다!
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2 changes: 1 addition & 1 deletion lessons/pl/chapter_10.yaml → lessons/pl/chapter_11.yaml
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- title: Rozdział 10 - Koniec
- title: Rozdział 11 - Koniec
content_markdown: >
Było mi niezmiernie przyjemnie mieć możliwość oprowadzenia Cię po zakamarkach języka Rust.
Ferris i cała załoga Przewodnika po Języku Rust życzy Ci wszystkiego najlepszego
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@@ -1,3 +1,3 @@
- title: Capítulo 10 - Fim
- title: Capítulo 11 - Fim
content_markdown: |
Isso é tudo por enquanto. Fique ligado para novos conteúdos. Espero que se divirta nesta jornada!
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