shell scripting topic

cyperghost

@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?

cyperghost

@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?

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.

cyperghost

@meleu Hello brother ;)
Yes I know it's maybe easy for me and you but take a look here
https://retropie.org.uk/forum/topic/12930/
I suggested the first solution (yours)
but it didn't work, so I used the "old" way.....

I bought now one of these mausberry devices to test ;)
It's really hard to test without the device.

AFAIK an alias can't be called within a script. So you may export the bash function with export -f func_call. But how this works? Do you have a clue?

meleu

@cyperghost said in shell scripting topic:

@meleu Hello brother ;)
Yes I know it's maybe easy for me and you but take a look here
https://retropie.org.uk/forum/topic/12930/
I suggested the first solution (yours)
but it didn't work, so I used the "old" way.....

I'll try to find what he made wrong. I think it was my fault: I didn't give really clear instructions for inexperienced Linux users.

I bought now one of these mausberry devices to test ;)
It's really hard to test without the device.

Oh yeah! Let's break that infinite loop!!

AFAIK an alias can't be called within a script.

I thought you were talking about creating an alias for shutdown command, making it call the killes.sh script before actually shutdown. But this approach has limitations.

So you may export the bash function with export -f func_call. But how this works? Do you have a clue?

When you export something in a shell (functions or variables) only the child shells will know the respective variable/function.

A good way would be to add this function and the export command to one of these files:

~/.profile
~/.bash_profile
~/.bashrc
/etc/profile
create a file at /etc/profile.d/ directory (btw, did you notice that you have a /etc/profile.d/10-retropie.sh on your RetroPie? :) )

But this approach also has its limitations...

lilbud

I have followed @meleu down the bash rabbit hole and need some help getting out.

I am trying to write a script for the retropie menu that will allow you to select the overlay you want, (kind of like the SNES Mini). That is where I get stuck.

My idea is this: When the script starts, it will list all of the overlays in a directory and allow you to select them. Upon selection, it will modify the overlay.cfg file and replace what is there, and finally start the game with the overlay applied.

Better example of what I am trying to accomplish: https://ghostbin.com/paste/avjcs

meleu

@lilbud it's possible. But you have to specify where do you want to apply the overlay (specific for a game? specific for a system?).

Expand the use case.

cyperghost

@lilbud Yes please - I can't imagine what you exactly want.
I think it can be wrapped up like here

lilbud

@meleu The script would apply the overlay to all systems automatically. Individual systems can be modified when launching a game from the system where the user doesn't want an overlay, like GB/GBC/GBA or other hand held systems were aspect ratio is not 4:3

@cyperghost Something like that would be nice for this, having the script and be able to choose which systems you want the overlay to be applied to.

cyperghost

@lilbud automatically means to invoke runcommand-onstart.sh
I think it's doable but we need more input about usecase...

I think there is a need of 2 parts....

Part let you choose overlay for special system
Invokes seleceted overlay to system on start of emulator run

I think.... you should start coding. And we will help you ;)
You can read the full thread I've posted ... The issue here was solved in an efficient way (imho)

meleu

@lilbud said in shell scripting topic:

@meleu The script would apply the overlay to all systems automatically.

I'm not sure if an overlay for all systems would look good. I think some systems have a different aspect ratio.

As @cyperghost said, we can help you once you start the coding. But maybe the fastest solution is to use rpie-art tool. Learning how to create an info.txt file is faster than learning a programing language.

Here is the info.txt creation doc: https://github.com/meleu/rpie-art/blob/master/INFO.md

cyperghost

@meleu Yes... therefore the runcommand-onstart. $1 shows current used system. So there is a way to set an overlay for a specfic system ... ;)

lilbud

@meleu @cyperghost I had this to start with:
sed -i 's/01.png/08.png/g' overlay.cfg

Something feels missing, not sure what at the moment.

meleu

@lilbud where is placed the script with that line of code? maybe you have to use the full path to the overlay.cfg.

lilbud

@meleu I believe it is placed in the overlay directory.

opt/retropie/configs/all/retroarch/overlay

cyperghost

@lilbud Just start coding use echo commands to show results in your bash
You can test sedcommands directly from CLI and results will be marked red.
Don't use -i parameter for testing... it will directly write to input file and may give unwantend results. If you want create altered files then work with direction > output-file first.

If all works then use -i

lilbud

@cyperghost Ok, I can get the original command to replace the text, but only if both fields are specified.

sed -i 's/01.png/08.png/g' overlay.cfg

This works fine, 01.png is replaced with 08.png. But what would I put in the first field if the overlay name is not 01.png. Something like this?:

sed -i 's/${FILENAME}.png/08.png/g' overlay.cfg

mitu

@lilbud You can use a wildcard:

sed -i 's/.*.png/08.png/g' overlay.cfg

Note that this will replace any <filename>.png in the file with 08.png.

cyperghost

@lilbud I'm still not sure what your goal is.
Anwer yourself:

Where is the overlay.cfg located?
In which case do you want to alter overlays?
Is there a "system" in altering names (Maybe $EMU-$ROMNAME-$TAG.png?)

Imho ... here's is a good script that writes several information in /boot/config.txt and checks existance of data before.

For graphics menu layout you can use this it uses arrays for graphics menu and here is a Howto for dialog/whiptail usage.

Here is the RetroPie wiki and how to input paramters into your script.

lilbud

@cyperghost okay

Overlay.cfg located in default directory, /opt/retrofit/configs/all/retroarch/overlay
The point of the script is to provide a way a to switch and choose the overlay from the retropie menu in ES.
So choosing overlay named, '08.png, will do a few things. It will check for an overlay in use. If one is found, then the cfg file will be modified to show the path of the wanted overlay.png, (/my/awesome/overlay/8.png).
Once the overlay is selected, the main retroarch.cfg will be modified with the viewport settings and the overlay.

Anything else needing further explanation?