Compress file as .tar.gz instead of .zip If I right click a file and I compress it I obtain a file.zip. Is it possible to set right click-->compress to produce a file.tar.gz as output? I always have to do it through terminal but many times I'd rather do it with a right click especially when I'm already in the finder looking at the folder
You can try to write a unix shell script where your commands are to tar the selected files then run gzip on it.

Then you can make this a service and save it at ~/Library/Services. Then enable it via system preferences > Keyboard > shortcuts > Services. 


Creating System-Wide Keyboard Shortcut To Launch Applications
How do I run my automator service without opening automator?


Then you can select a file and right-click on the selected file. At the bottom of the right click menu,  a section for Services appears which has your services. Select your new service and that should do the job.

Alternatively, it can be found in Finder menu > Services.