Escape sequences such as encodings of terminal commands and function keys

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4
votes
2answers
362 views

DEC ANSI command sequence questions; cursor movement

So I'm writing a terminal emulation (I know, I should just compile putty, etc.) and am at the stage of plodding through vttest to make sure it's right. I'm basing it on the VT102 for now but will add ...
3
votes
2answers
2k views

Trying to print up down arrow keys

I have this: I read down arrow key abc@abc-ubuntu:~/bashpratice$ read -n 3 key ^[[Babc@abc-ubuntu:~/bashpratice$ I am able to grep for it abc@abc-ubuntu:~/bashpratice$ echo $key | grep '\[' [B ...
2
votes
1answer
252 views

Modifying a set of binary files

I have several binary files with the character 0x04 in them, and I'd like to add an escape \ character before each. Is there a script I can use to do this without needing to manually edit each one?
4
votes
2answers
2k views

How to escape < or > in a parameter in shell?

I'd like to use grep with a PCRE expression that contains the < character. Bash thinks I want to redirect, but I don't want to. How can I escape <?
3
votes
1answer
283 views

Could someone please explain some of these escape codes?

I'm seeing this in my .bashrc file: PS1='${debian_chroot:+($debian_chroot)}\[\033[01;32m\]\u@\h\[\033[00m\]:\ [\033[01;34m\]\w\[\033[00m\]\$ ' and I have absolutely no idea what all those ...
14
votes
2answers
2k views

How to avoid escape sequence attacks in terminals?

Reading the details of CVE-2009-4487 (which is about the danger of escape sequences in log files) I am a bit surprised. To quote CVE-2009-4487: nginx 0.7.64 writes data to a log file without ...
20
votes
6answers
10k views

Removing control chars (including console codes / colours) from script output

I can use the "script" command to record an interactive session at the command line. However, this includes all control characters and colour codes. I can remove control characters (like backspace) ...
3
votes
2answers
372 views

Unix Shell and colours

Can any one please help me understand this code snippet that I found in .profile file echo -en "\e[32;44m $(hostname) \e[m";echo -e "\e[m"
4
votes
1answer
634 views

Reverse control-code look up for terminals

My understanding is that terminals often use ANSI control-codes to represent non-alphanumeric character sequences. For example, when editing .inputrc for Bash in Linux, it's easy to find code ...
4
votes
1answer
662 views

Re-escape brackets in PS1

As others have pointed out, color codes in PS1 should be bracketed by \[ and \] to avoid them taking up horizontal space. I've added the necessary code to .bashrc: highlight() { if [ -x ...
14
votes
2answers
2k views

Where do my ANSI escape codes go when I pipe to another process? Can I keep them?

I sometime want to pipe the color-coded output fror a process, eg. grep... but when I pipe it to another process, eg. sed, the color codes are lost... Is the some way to keep thes codes intact ? ...