Help.. How do i free up space from os x installer

[Keza]

My upgrade from Yosemite to el captain was interrupted and now when i boot up it goes straight to the os x installer and when i try to select my disk to install it says theres not enough free space...
When I reboot it just does this over and over and over.
I have tried the following:
Boot in recovery mode and selecting startup disk (nothing shows up)
Boot in recovery mode, go to Disk Utilities and repair disk (doesn't help)
Boot in recovery mode and re-install from there (gives the same error)
Can i delete files via terminal?
Any help appreciated

 

[honestone]

What exact Mac model are you using?

Do you have access to another Mac? (How are you making posts here?)

Do you happen to have a more robust disk maintenance program like Disk Warrior or TechTool Pro?

Do you have either the file "Install OS X Yosemite" or the file "Install OS X El Capitan" anywhere on your machine?

And, this is critical, have you been making any backups to an external device?