how to change the text console to 50 lines instead of 25

Edit /etc/lilo.conf and change
vga=something

to
vga=ask

Run /sbin/lilo and reboot.

Now when you restart it should show the compatible VGA modes. Eg:

1.  80x25
2.  80x43
3.  132x25
4.  132x43

Remember the precending number on the mode you want to use and after you've rebooted you should edit /etc/lilo.conf again and change
vga=ask

to
vga=your_chosen_number

Run /sbin/lilo again to install the new settings.

Marko

does it only take effect on local console ?
What about remote console e.g. telnet

Prolly the easiest way to resize a telnet screen is to use the above suggestion on the remote machine as well presuming of course that the telnet is from the CLI. If not, we'd need more info, such as the WM and Xwindows versions used.

I add the option vga=ask at lilo.conf and then run lilo to update
but when reboot, no prompt ask me for vga mode
it just stop at the graphical kernel selection screen

I am using RH 7

This is my lilo.conf

boot=/dev/hda
map=/boot/map
install=/boot/boot.b
prompt
timeout=50
vga=ask
message=/boot/message
linear
default=linux-2.4.3

image=/boot/vmlinuz-2.2.18pre11-va1.1
        label=linux
        read-only
        root=/dev/hda2

image=/boot/vmlinuz-2.4.3
        label=linux-2.4.3
        read-only
        root=/dev/hda2

I'm not so sure of RH7, but this works in Mandrake 8.0:

Run setup (in Mandrake that's located at  /usr/X11R6/bin/setup)

Choose "Boot configuration" and from there you can choose "LILO with text menu". I'm sure RH has something similar.

Marko