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This article will explain in detail how to run helloworld in the Python programming language. The content of the article is of high quality, so the editor shares it for you as a reference. I hope you will have some understanding of the relevant knowledge after reading this article.

Executable Python program

This section only applies to Linux/Unix users, but Windows users may also be curious about the * lines of the program. First we need to give the program executable permission through the chmod command, and then run the program.

$chmod axix helloworld.py $. / helloworld.py Hello World

The chmod command is used to change the mode of the file, giving all users in the system permission to execute the source file. We can then execute the program directly by specifying the location of the source file. We use. / to indicate that the program is in the current directory. To be more interesting, you can change your file name to just helloworld, and then run. / helloworld. In this way, the program still works because the system knows that it must run the program with the interpreter specified in line * * of the source file.

As long as you know the exact location of the program, you can run the program now-but what if you want your program to run from all locations? In that case, you can save your program in one of the directories in the PATH environment variable. Whenever you run any program, the system looks for the directories listed in the PATH environment variable. And then run that program. You can make your program available anywhere by simply copying the source file to one of the directories listed in PATH.

$echo $PATH

/ opt/mono/bin/:/usr/local/bin:/usr/bin:/bin:/usr/X11R6/

Bin:/home/swaroop/bin

$cp helloworld.py / home/swaroop/bin/helloworld

$helloworld

Hello World

We can use the echo command to display the PATH variable and prefix the variable name with $to indicate to shell that we need the value of the variable. We see that / home/swaroop/bin is one of the directories in the PATH variable. Swaroop is the user name used in my system. Usually, there is a similar directory in your system. You can also add the directory of your choice to the PATH variable-this can be done by running PATH=$PATH:/home/swaroop/mydir, where "/ home/swaroop/mydir" is the directory I want to add to the PATH variable.

This method is very useful when you want to run your program anytime and anywhere. It's like creating your own instructions, like cd or other Linux terminals or DOS prompt commands. Tip: for Python, a program, script, or software all means the same thing.

Get help

If you need quick information help from a Python function or statement, you can use the built-in help function. It is especially useful when you use the command line with a prompt. For example, run help (str)-- this shows the help of the str class. The str class is used to hold all kinds of text (strings) used by your program. The class is explained in detail in later chapters on object-oriented programming.

Note: press Q to exit the help. Similarly, you can get information about almost everything in the Python programming language. Use help () to learn more about help itself! If you want help with operators like print, you need to set the PYTHONDOCS environment variable correctly. This can be easily done with the env command in Linux/Unix.

$env PYTHONDOCS=/usr/share/doc/python-docs-2.4.3/html/

Python

Python 2.3.4 (# 1, Jul 26 2006, 16:42:40)

[GCC 3.4.2 20050110 (Red Hat 3.4.2-6.fc3)] on linux2

Type "help", "copyright", "credits" or "license" for

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