Escape sequences such as encodings of terminal commands and function keys

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3
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3answers
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How can I pass strings with single quotes to grep?

My desired outcome is the following: to recursively search a directory looking for a given string in all found files. The following command is my usual port of call: find ./ | xargs grep -ns 'foobar' ...
8
votes
4answers
5k views

How can I create a file with multiple lines from the command-line?

How can I enter the following contents in a file: Hi abcd I tried using echo "Hi\nabcd" >> ab.txt, but in the file it's written as is (the \n is included, instead of a newline)
4
votes
2answers
380 views

Is there a way to lock terminal's title?

Sometimes there're lots of different sessions opened in own terminal's tabs and it's rather desirable to have theirs initial titles (named by session name) locked since local title tweaks make those ...
8
votes
3answers
746 views

Escape sequences in output of script called from ncurses application

I'm currently running mcabber as my Jabber client (which uses ncurses) in a tmux session on my homeserver. Locally i run iTerm2 as a terminal emulator, which supports the triggering of growl ...
1
vote
1answer
1k views

Opening a file with space from Ruby

When I need to progmatically open in emacs a file that has a space in its name, how can I do that? I've tried these commands from a Ruby script, inside backquotes or popen(…): emacs "foo bar" or ...
3
votes
1answer
1k views

How to bypass GNOME Terminal when sending keyboard input?

When running an interactive shell application, how can I send it a key (or key combination) which would normally be intercepted by GNOME Terminal? In this particular instance it's the F10 key which is ...
4
votes
1answer
2k views

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 ...
10
votes
4answers
10k views

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
978 views

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 ...
11
votes
3answers
12k views

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
votes
1answer
2k views

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 ...
2
votes
2answers
2k views

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 ...
22
votes
6answers
19k views

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?
5
votes
1answer
2k views

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?
5
votes
2answers
391 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
258 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
3k 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
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 ...
16
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 ...
20
votes
6answers
12k 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
377 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
654 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
691 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 ? ...