... and also how do I start in the command mode....I've tried changing the runlevel to all the runlevels possible but but keeps on booting in the graphical environment
What did you use to try to change the runlevel before?
There is a config file '/etc/inittab' that contains the default runlevel setting. A default inittab usually has enough comments to help you understand it. there is probably a line similar to:
id:4:initdefault:
To enable the default console-based multiuser mode, change the line to:
id:3:initdefault:
Just in case your inittab doesn't have the comments, here are the runlevels:
# 0 = halt
# 1 = single user mode
# 2 = unused (but configured the same as runlevel 3)
# 3 = multiuser mode (default Slackware runlevel)
# 4 = X11 with KDM/GDM/XDM (session managers)
# 5 = unused (but configured the same as runlevel 3)
# 6 = reboot
For the sake of everyone involved, be VERY careful when editing this file!
Every distro is a bit different, but the problem with doing a chmod -x on gdm, is that somewhere in your rc scripts it may rollover to xdm, or kdm if gdm is not found/executable.