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Old 10-01-2012, 11:00 AM   #1
Registered: May 2009
Posts: 291

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What are these characters ^[[D^[[A^[[C^[[B^[[5~^[[6~^[[H^[[F^[[3~^[[2~ ?

When I execute a program that doesn't directly specify what up down left
right page up page down home end insert delete do or when I use telnet
the output is:

What the heck do they do? even when my program is waiting for input when I
type home or ^[[H it puts the string at the top of the buffer leaving the text
on it which is pretty cool to overwrite.Is it the kernel that does that or the
software developers who provide the kernel and if the kernel is there a reason
or is that just something that has been forgotten? tty3 doesn't recognize home
just konsole, that I know of so far. Hm yea my program doesn't recognize the
output when I proceed my input with one of those characters.

mmmmmmh scroll lock works.

Last edited by errigour; 10-01-2012 at 11:01 AM.
Old 10-01-2012, 11:17 AM   #2
Registered: Aug 2012
Location: Chiang Mai, Thailand
Distribution: Kubuntu 12.10 x86_64
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They are the escape codes. The Special keys on your keyboard do have their unique escape codes. They don't do much though... Just an example, if you press CTRL+A in the shell, it will beep.

Last edited by suttiwit; 10-01-2012 at 11:18 AM.
Old 10-01-2012, 11:24 AM   #3
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Those are X terminal control sequences; from the manual page:
telnet uses at least the HOME, SHELL, DISPLAY, and TERM environment variables. Other
environment variables may be propagated to the other side via the TELNET ENVIRON option.
Check your TERM environment with
echo ${TERM}
it may be linux or xterm (or something else entirely) and you'll need to set it when you get connected to whatever the remote system knows about (xterm is usually a good starting value). X terminal control sequences are DEC VT102/VT220 compatible and many remotes will recognize a TERM environment of one of those.

Read through the manual page and possibly use one or more of the command line options so telnet will "talk nice" with the remote.

Another option is to use ssh (if it's a Unix/Linux box on the other end) and you'll probably have a little better luck.

Hope this helps some.


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