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    shell scripting topic

    Scheduled Pinned Locked Moved Ideas and Development
    shellshell scriptprogramming
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    • SanoS
      Sano
      last edited by

      Hi guys, sorry, wasn't here for a while.
      I've read @meleu last post and I just checked "things", as I'm also not fond of the infinite loop. That said, I don't use mausberry or gpio either.

      Did you take a look at the gpio util from wiringpi ?
      http://wiringpi.com/the-gpio-utility/

      I found this option in the doc, that may help (if I understood your need) :

      gpio wfi <pin> rising/falling/both
      
      This causes GPIO to perform a non-busy wait on a single GPIO pin until it changes state to that indicated.
      
      1 Reply Last reply Reply Quote 2
      • cyperghostC
        cyperghost
        last edited by

        @meleu I have to say thank you for your detailed explanation. I'm currently on holidays ... so I'm a bit quieter in this forum for couple of days. I think during these days a few things will change to ES ...
        But I take my portable Pi to the airport with a copy of Terranigma on it (I deeply hope that I will save humankind during may holiday)...

        We are looping to check a file content every single second just to execute a command to SHUT DOWN THE WHOLE SYSTEM! In my head the thought is: "this script is wasting 99.99999% of its CPU time slice!".

        I understand you... about the inotify thing...
        But without the real hardware it's a bit a pain ... but it's solvable imho
        Maybe a chmod to the exported GPIO files will help.

          echo "$GPIOpin1" > /sys/class/gpio/export
          echo "in" >/sys/class/gpio/$GPIOpin1/direction
          chmod 660 /sys/class/gpio/$GPIOpin1/direction
          chmod 660 /sys/class/gpio/$GPIOpin1/value
        

        This subject would be a good nerdy chat while drinking some Caipirinhas when you come to Rio.

        Oh yes :) It's all about games ... As I told you it's more likely to expand to the eastern hemisphere but never say never and if I'm on buisness journey I'll surly come back to your offer.

        @Sano
        Welcome to this thread

        Yes I told also to use gpio-control. wPi is also a solution but I think this approach is an overkill to just monitor ONE Gpio. I use wPi in my work as it got's powerfull IRQ functions but you have to load a whole C programm to just monitor ONE GPIO and I think that's not attentend to be called "effective".

        Also think about you have to compile the thing and I think this approach isn't user friendly anymore. So way meleu want it to do is really nice. It comes very far to RT processing!

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        • cyperghostC
          cyperghost
          last edited by

          @meleu

          My new project is a portable device with 4,3" screen and I2S soundmodule.
          It has a foldable screen build in and if you open it you activate an trigger....
          As it is still useable with HDMI I have two /boot/config.txt

          One force activates HDMI and BCM sound
          The other deactivaes HDMI, activates SDTV and uses I2S sound

          So I coded a bash script that would exchange the the boot files in depence to the sensors.

          I've build in a LED that show status. If SDTV config is already active and the foldable monitor is open then it will boot
          If the SDTV config is active and the monitor is closed then LED will blink for a few seconds ... at this time you have the chance to open the LED screen. If not the config for HDMI will be exchanged and a reboot is forced.....

          So here is my code
          Bash is really a powerfull language, the functions call are super easy ;)

          This one is dedicated to you... because it wasn't possible without your help

          I hope you find some time to read the code and give opinion to the structure. Are the intenions setted right, are there some things in general to improve. This is not for puplic usage so if I set a file I know that I need it and I would not check .....

          https://ghostbin.com/paste/kqqcq

          meleuM 2 Replies Last reply Reply Quote 0
          • meleuM
            meleu @cyperghost
            last edited by

            @cyperghost dude, your coding style really improved! :-)

            I did a quick look and have two or three comments about the coding (didn't focused on the logic). Will do soon. I'm on the phone now.

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            • meleuM
              meleu @cyperghost
              last edited by

              @cyperghost Looks like a ghost got your code! I was going to make my comments now and the code isn't there.

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              • cyperghostC
                cyperghost @meleu
                last edited by cyperghost

                @meleu Sorry ;)
                I setted wrong timer - this will be alive for 7 days now. I'm just busy :( But I hope to come back soon with a RetroAchivments link to you ;)
                https://pastebin.com/LyA4dTwN

                Neustart > reboot
                Blinkschleife > loop for blinking
                Befehle > commands
                Wahl > selection
                Abfrage Hallsensor > request hall sensors

                Just to understand the comments a bit ;)

                meleuM 1 Reply Last reply Reply Quote 1
                • meleuM
                  meleu @cyperghost
                  last edited by meleu

                  @cyperghost I've created a gist for your script: https://gist.github.com/meleu/0ea0b96ccafdbd0a432cb5a59a8c1835

                  We can comment there! ;-)

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                  • meleuM
                    meleu @meleu
                    last edited by

                    @cyperghost I've just noticed that I don't receive notifications on a gist comment...

                    I answered some of your questions there. :-)

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                    • cyperghostC
                      cyperghost @meleu
                      last edited by

                      @meleu I created a new GIST ;)

                      meleuM 1 Reply Last reply Reply Quote 0
                      • meleuM
                        meleu @cyperghost
                        last edited by

                        @cyperghost and I answered your questions there too. ;)

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                        • cyperghostC
                          cyperghost @meleu
                          last edited by

                          @meleu
                          Thank you for all your help.... I've something for you

                          inkey() { char="" ; stty -icanon min 0 time 1 ; char=`dd count=1 2>/dev/null` ; }
                          

                          I hope you find that usefull ;)
                          source - Unix Linux Forums

                          meleuM 1 Reply Last reply Reply Quote 0
                          • meleuM
                            meleu @cyperghost
                            last edited by

                            @cyperghost Not sure what would be the purpose of that crazy function. I never programmed in Basic and don't know what INKEY$ does... :-)


                            bash lovers, I've found this doc and liked it: https://github.com/progrium/bashstyle

                            I didn't like every tip/recommendation there, but found it useful.

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                            • lilbudL
                              lilbud
                              last edited by

                              This post is more of a forewarning

                              Don't use climate on the raspberry pi. This program is made to simplify several terminal commands to one or two words, sounds good in theory. But it auto runs and takes up resources. My Pi was sitting idle with climate running and it was at 80 Celsius (176 fahrenheit)

                              Creator of the Radiocade: https://retropie.org.uk/forum/topic/6077/radiocade

                              Backlog: http://backloggery.com/lilbud

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                              • cyperghostC
                                cyperghost @meleu
                                last edited by cyperghost

                                @meleu You can interrupt loops with that.
                                But I have to test if this is working with keypads also. If yes you can trigger events by keypad press and don't need enter key

                                In BASIC (afaik) you wrote it like this.... ucase is a function for uppercase characters so you dont use check for "q" and "Q".

                                Retro: Do loop was introduced in QBasic in 1991, former there were just if-then clauses and the goto/gosub command - really spooky

                                REM inkey function for basic
                                REM in anicient basic $ for charstrings is obligatory 
                                PRINT "Press Q to quit"
                                DO : LOOP UNTIL UCASE$(INKEY$)="Q"
                                
                                !/bin/bash
                                # Demo do show function inkey
                                inkey() { char="" ; stty -icanon min 0 time 1 ; char=`dd count=1 2>/dev/null` ; }
                                
                                # ---- main -----
                                echo "Press some keys and I will show you keybuffer after 3 seconds"
                                sleep 3 && inkey
                                echo "You wrote \"$char\""
                                
                                meleuM 1 Reply Last reply Reply Quote 0
                                • meleuM
                                  meleu @cyperghost
                                  last edited by meleu

                                  @cyperghost be careful using this. It keeps your terminal busy and then you will be unable to input something to a simple read.

                                  Check this script (I just added one single line at the end of your demo):

                                  #!/bin/bash -
                                  inkey() { char="" ; stty -icanon min 0 time 1 ; char=`dd count=1 2>/dev/null` ;}
                                  
                                  # ---- main -----
                                  echo "Press some keys and I will show you keybuffer after 3 seconds"
                                  sleep 3 && inkey
                                  echo "You wrote \"$char\""
                                  
                                  read -p "Type something: " var
                                  

                                  And here is the error I've found:

                                  $ bash inkey.sh
                                  Press some keys and I will show you keybuffer after 3 seconds
                                  asdfgYou wrote "asdfg"
                                  Type something: inkey.sh: linha 10: read: erro de leitura: 0: Resource temporarily unavailable
                                  
                                  $ # and it messed my terminal even outside the script, look...
                                  
                                  $ read -p "Type something: " var
                                  Type something: -bash: read: erro de leitura: 0: Resource temporarily unavailable
                                  
                                  

                                  "erro de leitura" (pt_BR) == "reading error" (en)

                                  After this tests I used git to push some commits to one of my repos and when git asked my github username I've got that same error "Resource temporarily unavailable".

                                  The good thing is that you can "fix" your terminal using the reset command (yes, just type reset and then <ENTER>).

                                  I don't know the details of that stty command, but I think it's the responsible for the mess.

                                  Summing up: use that inkey trick very carefully. Maybe performming a reset command after using inkey function is a good idea. :-)

                                  Cheers!

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                                  • cyperghostC
                                    cyperghost
                                    last edited by

                                    @meleu Wow you are really master meleu

                                    #!/bin/bash
                                    # RESET is mandotary for releasing terminal from being busy
                                    # inkey function demo
                                    inkey() { char="" ; stty -icanon min 0 time 1 ; char=`dd count=1 2>/dev/null` ; }
                                    
                                    # ---- main -----
                                    
                                    echo "Press some keys and I will show you keybuffer after 3 seconds"
                                    sleep 3
                                    inkey && reset # <-- this is mandotary
                                    echo "You wrote \"$char\""
                                    
                                    read -p "Type something: " var
                                    echo $var
                                    

                                    I think this function is just a dirty trick. Thanks for looking deeper in. Just did a few simple tests with that.

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                                    • meleuM
                                      meleu
                                      last edited by

                                      @cyperghost talking about indentations in this thread to not messing that other.

                                      @meleu ;) How about the indentations?

                                      it really improved, I just would like to make one little note.

                                      This snippet here

                                      until [[ "${console[idx]}" == "$1" ]]
                                          do
                                             idx=$(( $idx + 1 ))
                                          done
                                      

                                      Could be better indented this way:

                                      until [[ "${console[idx]}" == "$1" ]]
                                      do
                                          idx=$(( $idx + 1 ))
                                      done
                                      

                                      It's a more common practice.

                                      I'm glad to see you improving your coding style! :-)

                                      Cheers!

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                                      • cyperghostC
                                        cyperghost
                                        last edited by

                                        @meleu About your newest ES-termination code.
                                        Is tty is setting the trigger to start the service? Don't get me wrong I thought tty is just the terminal like ssh ;) Can you please explain?

                                        cyperghostC 1 Reply Last reply Reply Quote 0
                                        • cyperghostC
                                          cyperghost @cyperghost
                                          last edited by

                                          @meleu
                                          Is there no annother approach?
                                          systemd is very complicated?
                                          Can we export a function call to shell that would end ES?
                                          Can we use an alias ... as it can't be used from scripts - is there annother way?

                                          meleuM 1 Reply Last reply Reply Quote 0
                                          • meleuM
                                            meleu @cyperghost
                                            last edited by meleu

                                            @cyperghost There are as many approaches as creativity allows. I just tried to find a way to encompass as many use cases as possible. The explanation for how it works can be complex, but the steps to make it work is not.

                                            Using an alias has its limitations, but it's an option.

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