Escape sequences such as encodings of terminal commands and function keys

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Escaping of meta characters in basic/extended posix regex strings in grep

Is it possible to escape all meta characters of a string inside a variable before passing it to grep? I know similar question has been asked before on SE (here) and also a good explanation here, but I ...
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4answers
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How to make the terminal display user@machine in bold letters?

I have seen in some screen-shots (can't remember where on the web) that the terminal can display the [username@machine /]$ in bold letters. I'm looking forward to getting this too because I always ...
5
votes
2answers
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is it possible to send a control sequence to a terminal emulator using the keyboard

If you type echo -e '\eZ' and hit return in a shell running in an xterm, you'll see that the terminal emulator prints an obscure code 1;2c. This seems to indicate that xterm interprets the VT100 ...
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3answers
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How to escape quotes in shell?

I'm having trouble with escaping characters in bash. I'd like to escape single and double quotes while running a command under a different user. For the purposes of this question let's say I want to ...
5
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1answer
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In Bash, why is PROMPT_COMMAND set to something invisible?

On RHEL6 and CentOS 6, /etc/bashrc sets PROMPT_COMMAND here: case $TERM in xterm*) if [ -e /etc/sysconfig/bash-prompt-xterm ]; then PROMPT_COMMAND=/etc/sysconfig/bash-prompt-xterm ...
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2answers
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Is the `\` character escaping or becoming part of my ssh key password

If I do: ssh-keygen -N password123\$ -f bobskeys Is \ escaping the $ character or becoming part of the password? Or rather, will bash be doing any escaping before ssh-keygen gets the password ...
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6answers
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How to clear terminal completely?

When we use clear command or Ctrl+L in terminal, it clears terminal but we can still scroll back to view the last used commands. Is there a way to completely clear the terminal?
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1answer
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How can I match the page break character in a regular expression?

Nano calls it ^L, but of course, typing something like $ grep -v "^\^L" file doesn't work. Its unicode codepoint is 000C. How can I match it in a regular expression?
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2answers
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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 ...
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2answers
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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 ...
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1answer
255 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?
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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 <?
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1answer
284 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 ...
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2answers
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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 ...
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6answers
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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) ...
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2answers
374 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
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1answer
649 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
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1answer
679 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 ...
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2answers
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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 ? ...