cursor control in console

Scott Castaline hscast at charter.net
Mon Oct 6 13:55:29 PDT 2008


Scott Castaline wrote:
> Jordan Bray wrote:
>>
>>     Possible issue #1, bash.  try running sh or even python at the
>>     command line, and see if the cursor works properly.  How does it
>>     handle ncurses?  AKA, if you do a make menuconfig in the kernel
>>     source directory, does everything work properly?  Also, are you
>>     using any console mouse program?
>>     Possible issue #2, some crazy program running.  try booting into
>>     single user mode (kernel argument su), and see how that works.
>>
>>     Hope that helps...
>>
>> Another possible issue is obviously the terminal.  Try performing a 
>> TERM=vt100 (i think thats right) (goodbye, colors).
>> Another issue is that sometimes the cursor on shells performs badly when 
>> there are characters on the last line when the program comes to an end.  
>> Type a quick echo to clear that.
>> A highly unlikely (now that I'm thinking about the terminal) possibility 
>> is a fouled up PS2 variable.  try performing an "echo ' " (with a single 
>> quote at the end), and when the new prompt comes up, see if the terminal 
>> is doing it's job properly.  Are there colors on the first part of the 
>> command line:
>> aka when you see this:
>> [code]
>> someuser at somehost:somedir$
>> [/code]
>> is any of that colorful?
>>
>> -- 
>> /me
>>
> While reading your response I had rebotted vbox vm to livecd and did a 
> lspci. I noticed 2 lines that were different that seems like when the 
> livecd was created they had the source code for the vbox guest additions 
> software for linux. The 2 lines are as follows, first from my created 
> LFS and then from the LiveCD:
> 
> 00:02.0 VGA compatible controller: Unknown device 80ee:beef
> 00:04.0 System peripheral: Unknown device 80ee:cafe
> 
> 00:02.0 VGA compatible controller: InnoTek Systemberatung GmbH 
> VirtualBox Graphics Adapter
> 00:04.0 System peripheral: InnoTek Systemberatung GmbH VirtualBox Guest 
> Service
> 
> Notice VirtualBox Guest Service for the 2nd line under LiveCD boot.
> 
> I will try your suggestions as well and let you know.
using vt100 didn't do anything. "echo '" gave me a > as though I was 
breaking up a long command over several lines. executing sh did 
eliminate some of the quirkiness in that it would just do the horizontal 
scroll. To simulate the behavior I'll just hold down the key to 
duplicate that character. What happens is the line with the prompt will 
fill up until aroungd character pos 72 then drop down to the neext line 
as though it was doing a \CR\LF of course no prompt on that line and 
continue printing out the character, only now it goes beyond pos # 72 
and does the horiz. scroll. I'll hit enter and of course the system 
response is no such command. I'll hit the up arrow to recall the last 
command line and the cursor will positioned several characters to the 
left of the last character position. If I hit the left arrow once then 
end it'll move the cursor to the end of the command line. I then 
backspace continuously untill it wipes out even the prompt but will 
leave a number of characters at the right end. If I hit enter my prompt 
comes back with the cursor in the right position. It's almost like 
something thinks that the command line is inverted with what it thinks 
is the prompt but to the right.



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