Quick boot to terminal comes handy, when you want to make full system update (yum update) or maintenance. You can boot into terminal without using a rescue disk or installation media by following these steps.
1. When your system boots, pause with the grub menu.
2. Highlight your OS to which you want to boot. Press 'e' then.
3. Highlight kernel (that will be second in the menu) and press 'e' again.
4. Without changing the kernel arguments, add '3' with space (without quotes). Press enter. 3 is runlevel for terminal with networking support.
5. This goes back to grub menu with kernel highlighted. Press 'b' to boot into.
Thats it! you will be booted to terminal. Do your gui-enemy stuffs there.
You can also prefer different run levels in kernel arguments (step 4).
Run levels in fedora:
1 -Single-User mode
2 -Multi-user mode console logins only (without networking)
3 -Multi-User mode, console logins only
5 -Multi-User mode, with display manager as well as console logins (X11)
For other distributions, please refer here