where is the file that contains all the info on the players that have joined your server?
What do you mean by all the info? That is very vague. If you add -condebug to your start up it will make a convenient console.log file logging everything that happens including player connects.
Like there has to be a file that keeps the players info so that it keeps say shop items and things liek that
That all depends on what shop you’re using?
I just need to get the persons steam id that joined a week ago if thats posible
It’s kind of unlikely if you have logging disabled. If you use ULX you could check /garrysmod/data/ulx for any log files and if not then try garrysmod/logs/ but there will probably be tons of files in there and it will be hard to find what you’re looking for.