Escape sequences such as encodings of terminal commands and function keys

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4
votes
2answers
5k 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
299 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 ...
19
votes
2answers
3k 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 ...
27
votes
6answers
18k 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
384 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
735 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
820 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 ...
17
votes
2answers
3k 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 ? ...