I am looking to create some scripts that I will need for my SharePoint, but my power-shell skills are very bad. Is there any good tutorial that will help me become better at it ? It can be anything and it should start from the basics. I have windows server 2012 r2 and SharePoint 2013.
I think it's very hard to have a comprehensive tutorial for SharePoint 2013 powershell. There's so much you can do and to condense all of that into a guide is hard. I would try starting at Technet: Google tasks that you might think you'd need to complete. (Again, everyone uses SharePoint for different reasons, and so that'd also make a 'complete guide' hard to come by).
A simple start is:
Once you get comfortable, trying (perhaps in a sandbox environment) to create items using PowerShell. These all start with New-SP___________. Try New-SPWebApplication (http://technet.microsoft.com/en-us/library/ff607931(v=office.15).aspx) to start and get a feel for PowerShell syntax and what will usually happen.
It's important to keep in mind that some tasks don't happen automatically, so when in doubt, wait a few minutes to see if PowerShell responds before going to drastic measures.
I haven't written extremely nice scripts like experts on the internet, so I'm only a provision-farm-and-service-applications-and-web-applications kind of PowerShell user. I hope that helps, though.
Sorry I can't help with more complicated scripts.
there are a few introductory things you need to be aware of
btw, Catherine made some good points herself, specially about verbs (get, set, new), so make sure to check them out
this is getting too long but i still want to point out a few common cmdlets