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Raspberry Pi, combining commands

Former Member

Hi, so I am new to programming on the Pi, but am able to find most of the answers I want on how either I am having trouble finding an answer for the problem I am having.

 

At the moment I am playing around with LED's and buttons and am currently trying to combine and groups commands, what I mean by this is for example I have multiple LED's and am creating a sequence of turning them on and off but to save time instead of having to write the whole line of code to turn each LED on and off I would like to be able to write the command once and then rename it to fir example LED1on or LED3off.

 

I hope I have explained my self and if not just let me know and I will try and reword it.

 

Thanks

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  • in reply to johnbeetem

    Henry,

       John gave a very good reference for examples.

     

    To explain a little bit more, there are commands that you type interactively

    at the "shell" prompt, such as 'ls' and 'pwd'.  You can use a text editor to create

    a file and put any of those shell commands into the file, then close the file,

    and then make the file executable, by typing

             chmod  +x  somefilename

    Then you can run the commands in the file from the command line by typing

    the name of the file.  To avoid any possible confusion with other files with the

    same name in other directories, it is safest to use './" in front of the file name, such as

          ./somefilename

     

    The './" means to use the file in the current directory (because '.' means current directory

    and '/' is the separator between directory names and file names).

     

    Alternatively, you could run the file by typing

        bash ./somefilename

    which is maybe less convenient, but doesn't require the 'chmod' step.

     

    bash is a shell command interpreter.  You can see an example from John's link.

    Besides putting simple commands in a bash script, you can add parameters to the

    script, just like the 'cat' command takes a parameter of which file to display.

    Typing 'man bash' will give you the manual for bash.

     

    Besides shell scripts, you can also put your commands in an interpreted programming

    language script, such as python, which also has an example in John's link.  That allows

    you do do more complex things in your script than you can do using bash.