102 lines
3.5 KiB
Markdown
102 lines
3.5 KiB
Markdown
# Hello World
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The classical introductory exercise. Just say "Hello, World!".
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["Hello, World!"](http://en.wikipedia.org/wiki/%22Hello,_world!%22_program) is
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the traditional first program for beginning programming in a new language
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or environment.
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The objectives are simple:
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- Write a function that returns the string "Hello, World!".
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- Run the test suite and make sure that it succeeds.
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- Submit your solution and check it at the website.
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If everything goes well, you will be ready to fetch your first real exercise.
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# Welcome to Bash!
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Unlike many other languages here, bash is a bit of a special snowflake.
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If you are on a Mac or other unix-y platform, you almost definitely
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already have bash. In fact, anything you type into the terminal is
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likely going through bash.
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The downside to this is that there isn't much of a development
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ecosystem around bash like there is for other languages, and there are
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multiple versions of bash that can be frustratingly incompatible. Luckily
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we shouldn't hit those differences for these basic examples, and if you
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can get the tests to pass on your machine, we are doing great.
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## Installation
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As mentioned above, if you are on a unix-like OS (Mac OS X, Linux, Solaris,
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etc), you probably already have bash.
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## Testing
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As there isn't much of a bash ecosystem, there also isn't really a de
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facto leader in the bash testing area. For these examples we are using
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[bats](https://github.com/sstephenson/bats). You should be able to
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install it from your favorite package manager, on OS X with homebrew
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this would look something like this:
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```
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$ brew install bats
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==> Downloading
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https://github.com/sstephenson/bats/archive/v0.4.0.tar.gz
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==> Downloading from
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https://codeload.github.com/sstephenson/bats/tar.gz/v0.4.0
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########################################################################
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100.0%
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==> ./install.sh /opt/boxen/homebrew/Cellar/bats/0.4.0
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🍺 /opt/boxen/homebrew/Cellar/bats/0.4.0: 10 files, 60K, built in 2
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seconds
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```
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Run the tests with:
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```bash
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bats hello_world_test.sh
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```
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After the first test(s) pass, continue by commenting out or removing the
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`[[ $BATS_RUN_SKIPPED == true ]] || skip`
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annotations prepending other tests.
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To run all tests, including the ones with `skip` annotations, run:
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```bash
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BATS_RUN_SKIPPED=true bats hello_world_test.sh
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```
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## Source
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This is an exercise to introduce users to using Exercism [http://en.wikipedia.org/wiki/%22Hello,_world!%22_program](http://en.wikipedia.org/wiki/%22Hello,_world!%22_program)
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## External utilities
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`Bash` is a language to write "scripts" -- programs that can call
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external tools, such as
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[`sed`](https://www.gnu.org/software/sed/),
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[`awk`](https://www.gnu.org/software/gawk/),
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[`date`](https://www.gnu.org/software/coreutils/manual/html_node/date-invocation.html)
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and even programs written in other programming languages,
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like [`Python`](https://www.python.org/).
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This track does not restrict the usage of these utilities, and as long
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as your solution is portable between systems and does not require
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installation of third party applications, feel free to use them to solve
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the exercise.
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For an extra challenge, if you would like to have a better understanding
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of the language, try to re-implement the solution in pure `Bash`,
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without using any external tools. Note that there are some types of
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problems that bash cannot solve, such as performing floating point
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arithmetic and manipulating dates: for those, you must call out to an
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external tool.
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## Submitting Incomplete Solutions
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It's possible to submit an incomplete solution so you can see how others
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have completed the exercise.
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