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    • 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]
          
          1 Reply Last reply Reply Quote 0
          • 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 1 Reply Last reply Reply Quote 2
                    • 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 ....

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

                                      @meleu I really deserve no special credit for this, I just remembered something like this existed, probably had to use it in the past, too :)

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                                      • cyperghostC
                                        cyperghost
                                        last edited by cyperghost

                                        A common mistake is often made by using grep.
                                        It is often told that grep finds a total of all search strings within a text file due the -c switch. That is total nonsense .... -c just counts lines

                                        So we miss

                                        hello hello hello hello
                                        hello
                                        
                                        grep -c hello
                                        2
                                        

                                        We use a small hack ;)
                                        Better is to use the -o option is will show occourences of search string listed in newline and now we pipe to wc -l ... and count lines again - now we catched them all ;)

                                        hello hello hello hello
                                        hello
                                        
                                        grep -o hello | wc -l
                                        5
                                        
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                                        • cyperghostC
                                          cyperghost
                                          last edited by cyperghost

                                          @meleu

                                          EDIT BEGIN
                                          I think I found a good solution with pure bash
                                          But maybe some knows a better one ;)

                                          val=${#Unix[@]}
                                          for ((i=0; i<$val; i+=1)); do
                                          

                                          EDIT END


                                          Is there something that can be made easier (more efficient) than this script?
                                          I want to merge two arrys
                                          A1=(1 2 3)
                                          A2=(one two there)
                                          the result should be A3
                                          A3=(1 one 2 two 3 three)

                                          It works with this script.
                                          But first... I want to avoid any counters (if possible)
                                          Do you know a nice trick to count up values {0..6} works only with fixed characters not as variable. So {0..6} is fine {0..$arraysize} not

                                          #!/bin/bash
                                          # A small script to show how to merge two arrays
                                          # with alternating values (exp. for creating arrays for dialogs)
                                          
                                          # Example Array
                                          Unix=("Debian" "Red hat" "Ubuntu" "Suse" "Fedora" "UTS" "OpenLinux")
                                          Shell=("bash" "csh" "jsh" "rsh" "ksh" "rc" "tcsh")
                                          
                                          # Check if both arrays got some size
                                          [[ ${#Unix[@]} -eq ${#Shell[@]} ]] || exit 1
                                          echo "Both arrays got same size -- Proceed"
                                          
                                          val=$((${#Unix[@]}-1))
                                          echo $val
                                          for i in $(seq 0 $val); do
                                              echo "Merging ${Unix[$i]} and ${Shell[$i]}"
                                              UnixShell+=("${Unix[$i]}" "${Shell[$i]}")
                                          done
                                          
                                          echo "${UnixShell[@]}"
                                          
                                          meleuM 1 Reply Last reply Reply Quote 0
                                          • meleuM
                                            meleu @cyperghost
                                            last edited by

                                            @cyperghost both methods are perfectly valid (using a for to iterate through all items).

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