- #Basic programming language sample codes how to#
- #Basic programming language sample codes install#
- #Basic programming language sample codes code#
- #Basic programming language sample codes windows#
This can easily be rectified by using the chmod command to add execute permission to our script: chmod 755 hello.rb This is simply a matter of the script not having execute permission. hello.rbĬlearly if you got the above output, there is a problem. We can now try running our hello.rb script. Given that ruby is in /usr/bin on the above system we can modify our sample application accordingly: #!/usr/bin/ruby Assuming it is already in your PATH environment variable you can use the which command to find it: which ruby This special line consists of a '#', a '!' and the path to the ruby executable and is known affectionately as the shebang.įirstly, you need to know where ruby is located on your system. This can be achieved on Linux or UNIX by placing a special line at the top of the script file informing the environment responsible for executing the program (such as a Linux command shell) where to look for the Ruby interpreter. Suppose, however, that we want to go one step further and be able to execute a Ruby based program simply by typing the name of the file containing the code, rather than prefixing it with the ruby command.
#Basic programming language sample codes code#
Placing Ruby code into a file is obviously much easier and practical than using multiple -e command line options. Ruby truly is an interactive, interpreted language.Ĭreating a Self Contained Ruby Executable on Linux or UNIX We could also perform a calculation or two: irb(main):002:0> 3 + 4Īs you can see, anything we type at the irb prompt gets executed as soon as we press the Enter key. Now, we can begin to execute Ruby code: irb(main):001:0> puts 'Hello Ruby' Once irb is installed, launch it as follows: $ irb
#Basic programming language sample codes install#
On Debian, Ubuntu or other Debian derived Linux distributions use the apt-get tool: sudo apt-get install irb On Red Hat or Fedora Linux this can be achieved as follows: su If you do not get the appropriate version information displayed, you will need to install irb. Verify the installation as follows: irb -v If you are running on Linux, there is a good chance irb is not yet installed.
#Basic programming language sample codes windows#
If you are running Windows and installed Ruby using the one click installer, you already have irb installed. Interactive Ruby code is entered using the irb tool. This is a great way to learn Ruby and to try out different code structures. One of the advantages of being an interpreted language is that we can write Ruby code directly into the interpreter and have it executed interactively and in real-time. This essentially means that Ruby source code is compiled and executed at run time, rather than pre-compiled as is the case with languages such as C or C++. In the What is Ruby? we discussed the fact that Ruby is an interpreted language. This can be done in a number of ways, each of which will be covered in the following sections of this chapter.
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#Basic programming language sample codes how to#
Before we go any further we need to learn how to execute our first Ruby example.
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Programming languages such as Java require a significant amount of structure before even the simplest of tasks can be performed. Hopefully, you are now beginning to see why Ruby is so popular. Clearly it would be hard to make printing a line of text any easier than a print statement followed by the text to be displayed (together with a newline character '\n' on Linux and UNIX).Īs an example, let's compare this to the equivalent code in Java: import java.io.* You may recall if you have read the previous chapters that one of the strengths of Ruby is that it is fast and intuitive to learn. On Linux or UNIX derived operating systems: print "Hello Ruby!\n"Īs you can see, all we need to do to output some text is enter a single line of Ruby code. Without further delay, let's get started: Ruby Essentials is no exception to this rule, though we will modify it slightly to display "Hello Ruby!". Typically such a program does nothing but output the string "Hello World" to the console window. Programming guides tend to follow the tradition of using "Hello World" as the first example of using a programming language.