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    Scheduled Pinned Locked Moved Ideas and Development
    shellshell scriptprogramming
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    • hiulitH
      hiulit @meleu
      last edited by

      @meleu Thanks! That's what I thought. I'll create some functions then, as you did ;)

      My little contributions to the RetroPie project:

      • Shell-Script-Boilerplate
      • Fun-Facts-Splashscreens
      • Limit-Last-Played-Games
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      • hiulitH
        hiulit
        last edited by

        Hi there!
        Can somebody help me figure this out?

        I have an argument passed to a shell script fun-facts-splashscreens.sh --create-fun-fact that can have:

        • no options
        • 1 option [system]
        • 2 options [system rom]

        How can I write a help message? --create -fun-fact [] [system] [system rom]?

        Thanks!

        My little contributions to the RetroPie project:

        • Shell-Script-Boilerplate
        • Fun-Facts-Splashscreens
        • Limit-Last-Played-Games
        mituM 1 Reply Last reply Reply Quote 0
        • mituM
          mitu Global Moderator @hiulit
          last edited by

          @hiulit Add a -h option and display the help when this option is passed to the script.

          hiulitH 1 Reply Last reply Reply Quote 0
          • hiulitH
            hiulit @mitu
            last edited by

            @mitu I'm sorry, I didn't explain myself clearly enough.

            I already have a -h option that shows all the options available. What I meant is, how should I tell the user that the option --create-fun-fact can have:

            • no options
            • 1 option [system]
            • 2 options [system rom]

            That's what I've come up with: --create-fun-fact [] [system] [system rom]
            Is that correct?

            Did I explain myself better this time? :P

            My little contributions to the RetroPie project:

            • Shell-Script-Boilerplate
            • Fun-Facts-Splashscreens
            • Limit-Last-Played-Games
            mituM meleuM 2 Replies Last reply Reply Quote 0
            • mituM
              mitu Global Moderator @hiulit
              last edited by

              @hiulit said in shell scripting topic:

              --create-fun-fact [] [system] [system rom]

              Ah, ok. I think the correct syntax would be

              --create-fun-fact [SYSTEM] [ROM]
              

              Usually an argument in brackets ([arg]) means the argument is optional.

              hiulitH 1 Reply Last reply Reply Quote 0
              • hiulitH
                hiulit @mitu
                last edited by

                @mitu I see! And if an argument is NOT optional? I have some of those around :P

                My little contributions to the RetroPie project:

                • Shell-Script-Boilerplate
                • Fun-Facts-Splashscreens
                • Limit-Last-Played-Games
                mituM 1 Reply Last reply Reply Quote 0
                • mituM
                  mitu Global Moderator @hiulit
                  last edited by

                  @hiulit If it's not optional, just remove the brackets.

                  --create-fun-fact system [rom]
                  
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                  • meleuM
                    meleu @hiulit
                    last edited by meleu

                    @hiulit can you explain the use case and provide some examples?

                    I'm sure we can find ways to make an option have zero, one or two options, but from a user point of view I think it's a bit confusing.

                    EDIT:
                    I can't see what would be the use for --create-fun-fact system rom, but if it's intended to be used on RetroPie, you can detect the system by looking the directory where the rom is located.

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                    • hiulitH
                      hiulit @meleu
                      last edited by

                      @meleu I'll try to explain myself even better than the last time :P Here we go!

                      This all comes from the fun-facts-splashscreens-runcommand-onend.sh that has these lines:

                      SYSTEM="$1"
                      ROM_PATH="$3"
                      sudo "$SCRIPT_DIR/fun-facts-splashscreens.sh" --create-fun-fact "$SYSTEM" "ROM_PATH"
                      

                      This is what creates the launching images when stoping the game. This is something the user doesn't need to care about. But then I already had --create-fun-fact in the help message so I wanted to let the user use it, like this:

                      • --create-fun-fact with no options passed creates a boot splashscreen.
                      • --create-fun-fact [SYSTEM] (SYSTEM can be all or any RetroPie system) creates launching images for all the systems, or the given system with the system's logo (and console if it exists).
                      • --create-fun-fact [SYSTEM] [ROM] (ROM can be an absolute path or just the ROM's name + ext, and then it takes the given system to look for the path) creates a launching image for the game.

                      Examples:

                      • --create-fun-fact
                      • --create-fun-fact all
                      • --create-fun-fact megadrive
                      • --create-fun-fact megadrive "/home/RetroPie/megadrive/Sonic the Hedgehog.zip"
                      • --create-fun-fact megadrive "Sonic the Hedgehog.zip"

                      I can see that from the user's perspective it could be a little confusing... Maybe it's better to split --create-fun-fact into two separate functions --create-fun-fact-boot-splashscreen and --create-fun-fact-launching-images.

                      Maybe I should remove this option from the help message? Just have it for myself to test?
                      That's something that can be done via the GUI, btw:

                      0_1522918743191_2018-04-03-181738_727x465_scrot.png

                      1_1522918743201_2018-04-03-181800_727x465_scrot.png

                      My little contributions to the RetroPie project:

                      • Shell-Script-Boilerplate
                      • Fun-Facts-Splashscreens
                      • Limit-Last-Played-Games
                      meleuM 1 Reply Last reply Reply Quote 0
                      • meleuM
                        meleu @hiulit
                        last edited by

                        @hiulit You wouldn't want to create a launching image for Sonic using a NES splashscreen, would you? Well, my suggestion below does not have this kind of flexibility, but here it go:

                        help message

                        --create-fun-fact [system|path/to/a/ROM]     no arguments = create boot splashscreen
                                                                     system = create a launching image for system
                                                                     ROM = create a launching image for a ROM
                        

                        If you wanna use this approach, please write a better help message for this option! ;)

                        code

                        #!/bin/bash
                        
                        user="$SUDO_USER"
                        [[ -z "$user" ]] && user="$(id -un)"
                        home="$(eval echo ~$user)"
                        
                        readonly RP_DIR="$home/RetroPie"
                        readonly RP_ROMS_DIR="$RP_DIR/roms"
                        readonly RP_CONFIG_DIR="/opt/retropie/configs"
                        
                        function get_options() {
                        
                            case "$1" in
                        
                        #H --create-fun-fact [system|path/to/a/ROM]     no arguments = create boot splashscreen
                        #H                                              system = create a launching image for system
                        #H                                              ROM = create a launching image for a ROM
                                --create-fun-fact)
                                    if [[ -z "$2" ]]; then
                                        # NOTE: for this usecase the --create-fun-fact MUST be the
                                        #       last parameter used in the command line.
                                        echo "Let's create a boot splashscreen with a fun fact!"
                        
                                    elif [[ -f "$2" ]]; then
                                        # NOTE: if it's a regular file, let's check if it's a ROM and
                                        #       create a splashscreen for this game.
                                        local rom_full_path="$(realpath "$2")"
                        
                                        if [[ "$rom_full_path" != "$RP_ROMS_DIR"* ]]; then
                                            echo "ERROR: \"$2\" is not on a valid ROM directory" >&2
                                            exit 1
                                        fi
                        
                                        # Reference for the tricks used to get the system's name below:
                                        # http://www.tldp.org/LDP/abs/html/parameter-substitution.html#PSOREX2
                                        system="${rom_full_path#$RP_ROMS_DIR/}"
                                        system="${system%/*}"
                        
                                        echo "Let's create a launching image for \"$2\" using the ${system}'s one!"
                        
                                    elif [[ -d "$RP_CONFIG_DIR/$2" ]]; then
                                        echo "Let's create a launching image for \"$2\" system!"
                        
                                    else
                                        echo "ERROR: \"$2\": invalid argument." >&2
                                        exit 1
                                    fi
                                    ;;
                        
                        #H --help                                       Print the help message and exit.
                                --help|-h)
                                    sed '/^#H /!d; s/^#H //' "$0"
                                    echo
                                    exit 0
                                    ;;
                            esac
                        }
                        
                        get_options "$@"
                        

                        testing

                        $ ./cff.sh --create-fun-fact
                        Let's create a boot splashscreen with a fun fact!
                        
                        $ ./cff.sh --create-fun-fact abcd
                        ERROR: "abcd": invalid argument.
                        
                        $ ./cff.sh --create-fun-fact nes
                        Let's create a launching image for "nes" system!
                        
                        $ ./cff.sh --create-fun-fact ~/RetroPie/roms/nes
                        ERROR: "/home/meleu/RetroPie/roms/nes": invalid argument.
                        
                        $ ./cff.sh --create-fun-fact ~/RetroPie/roms/nes/Contra\ \(USA\).zip 
                        Let's create a launching image for "/home/meleu/RetroPie/roms/nes/Contra (USA).zip" using the nes's one!
                        
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                        hiulitH 1 Reply Last reply Reply Quote 0
                        • hiulitH
                          hiulit @meleu
                          last edited by hiulit

                          @meleu Thanks for your reply! And no, I wouldn't want that

                          launching image for Sonic using a NES splashscreen
                          But my script prevents from doing that.

                          I'll try to paste every piece of code that I have, because it's very similar to what you have:

                          -cff|--create-fun-fact)
                              is_fun_facts_empty
                              if [[ -z "$2" ]]; then
                                  create_fun_fact
                              else
                                  shift
                                  create_fun_fact "$@"
                                  shift
                              fi
                              ;;
                          

                          If no arguments are passed called create_fun_fact without arguments, if there are any arguments, pass them all.

                          function create_fun_fact() {
                              if [[ -z "$1" ]]; then
                                  create_fun_fact_boot
                              else
                                  create_fun_fact_launching "$@"
                              fi
                          }
                          

                          There's more things going one here, but it basically calls one function or another depending on if there are arguments.
                          create_fun_fact_boot is self explanatory.
                          create_funfact_launching takes all the arguments and then:

                          function create_fun_fact_launching() {
                              local system="$1"
                              local rom_path="$2"
                          
                              if [[ "$system" == "all" ]]; then
                                  // Loop all systems and call create_fun_fact_launching "$system"
                              else
                                  if [[ -n "$rom_path" ]]; then
                                      // Check if $system it's the same in "rom_path"
                                      if true
                                          // Create launching image for the game
                                      else
                                          // Create launching image for the system
                                  else
                                      // Create launching image for the system
                                  fi
                              fi
                          }
                          

                          More or less that what I do. I think it's similar of what you wrote.

                          But then again, I think maybe it's better to to have 2 separate options:

                          • --create-fun-facts-boot-splashscreen(doesn't accept any argument)
                          • --create-fun-facts-launching-images (accepts system and rom)

                          EDIT:
                          You can take a look for youself https://github.com/hiulit/RetroPie-Fun-Facts-Splashscreens/blob/new-gui-menu/fun-facts-splashscreens.sh ;)

                          My little contributions to the RetroPie project:

                          • Shell-Script-Boilerplate
                          • Fun-Facts-Splashscreens
                          • Limit-Last-Played-Games
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                          • meleuM
                            meleu
                            last edited by

                            I've just found this and decided to share here:

                            Pure Bash Bible

                            The goal of this book is to document known and unknown methods of doing various tasks using only built-in bash features. Using the snippets from this bible can help remove unneeded dependencies from scripts and in most cases make them faster.

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                            • cyperghostC
                              cyperghost @meleu
                              last edited by cyperghost

                              @meleu Wow this is really helpfull ;) Cool snippets for bash coders. Thank you so much.

                              For ex:
                              Reverse array I did

                              for ((z=${#array[*]}-1; z>-1; z--)); do
                                     echo "${array[z]}"
                              done
                              

                              Reverse array with the bash-bible

                              ## Reverse an array
                              
                              # ```sh
                              reverse_array() {
                                  # Usage: reverse_array "array"
                                  shopt -s extdebug
                                  f()(printf '%s\n' "${BASH_ARGV[@]}"); f "$@"
                                  shopt -u extdebug
                              }
                              # ```
                              

                              Up to now my version seems a bit less complex. Maybe it's due my limited coding skills. I'm still learning ....

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                              • cyperghostC
                                cyperghost
                                last edited by cyperghost

                                @meleu I think that's just a note to me ... BashPitfalls

                                function1(){
                                    local status=$(false)
                                    echo $?
                                }
                                

                                Will return 0 which is obviously wrong
                                So the return code 0 just indicates the correct setting of a local setted value, which was correctly done ;)

                                So to get out of this make following

                                function1(){
                                    local status
                                    status=$(false)
                                    echo $?
                                }
                                

                                This will put out correct value for "error" 1

                                That's all folks

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

                                  @cyperghost yeah, that's a thing to be careful. I learned it while reading the RetroPie's Shell Style Guide: https://retropie.org.uk/docs/Shell-Style-Guide/#use-local-variables

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                                  • meleuM
                                    meleu
                                    last edited by

                                    I would like to share a little trick I learned today and also ask for some help...

                                    First the short story

                                    I was needing to check if the current hour is after 18h, then I tried this:

                                    hour=$(date +%H)
                                    if [[ $hour -gt 18 ]]; then
                                        echo "do something..."
                                    fi
                                    

                                    And then I got this error (please, forgive the non-english):

                                    -bash: [[: 08: valor muito grande para esta base de numeração (token de erro é "08")
                                    

                                    As you can see, the problem is that date +%H returns 08, and when I try to compare it, bash doesn't see 08 as a decimal number.

                                    The solution is obviously getting rid of that leading zero. I decided that using sed would be overkill for such a simple task, then I've found a pure bash solution using a feature of $(( )).

                                    hour=$(date +%H)
                                    hour=$(( 10#$hour ))  # could also be an oneliner: $(( 10#$(date +%H) ))
                                    if [[ $hour -gt 18 ]]; then
                                        echo "do something..."
                                    fi
                                    

                                    And now my script is working perfectly!

                                    Now the help I mentioned earlier on the beginning of this post...

                                    On that stackoverflow answer I see this:

                                    The $(( )) sets up an arithmetic context and the 10# converts the number from base 10 to base 10 causing any leading zeros to be dropped.

                                    Alright, but I like to see stuff on the official documentation in a hope to learn more tricks. The $(( )) is a bash builtin feature, but in the official documentation there's no mention to the 10# operand.

                                    Any thoughts on where to get info about it?

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                                    SanoS 1 Reply Last reply Reply Quote 0
                                    • SanoS
                                      Sano @meleu
                                      last edited by

                                      @meleu That I can answer !
                                      Actually it's in the very doc you mention :
                                      https://www.gnu.org/software/bash/manual/bash.html#Shell-Arithmetic

                                      Constants with a leading 0 are interpreted as octal numbers. A leading ‘0x’ or ‘0X’ denotes hexadecimal. Otherwise, numbers take the form [base#]n, where the optional base is a decimal number between 2 and 64 representing the arithmetic base, and n is a number in that base. If base# is omitted, then base 10 is used. When specifying n, the digits greater than 9 are represented by the lowercase letters, the uppercase letters, ‘@’, and ‘_’, in that order. If base is less than or equal to 36, lowercase and uppercase letters may be used interchangeably to represent numbers between 10 and 35.

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

                                        @sano whoops! Didn't catch those little words 😅

                                        Thanks Sano-san. And yeah, I learned more tricks!

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                                        • SanoS
                                          Sano @meleu
                                          last edited by

                                          @meleu Just FYI, you could just have used date +%-H ;)
                                          Glad to see you here again BTW !

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

                                            @sano ouch! Looks like I need RTFM some more...

                                            From the date man page:

                                                   By default, date  pads  numeric  fields  with  zeroes.   The  following
                                                   optional flags may follow '%':
                                            
                                                   -      (hyphen) do not pad the field
                                            

                                            Thanks again, Sanso-sensei!

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