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61
votes
7answers
4k views

How safe is it to cat an arbitrary file?

Sometimes when I cat a binary file by mistake, my terminal gets garbled up. Nothing a quick reset can't fix, but couldn't an attacker theoretically create a file that, when displayed on a terminal, ...
30
votes
5answers
23k views

Can't use exclamation mark (!) in bash?

I'm trying to use the curl command to access a http url with a exclamation mark (!) in its path. e.g: curl -v "http://example.org/!287s87asdjh2/somepath/someresource" the console replies with bash: ...
26
votes
8answers
2k views

Dealing with file names with special first characters (ex. ♫)

I have recently come across a file whose name begins with the character '♫'. I wanted to copy this file, feed it into ffmpeg, and reference it in various other ways in the terminal. I usually ...
22
votes
7answers
30k views

What is `^M` and how do I get rid of it?

When I open the file in vim I am seeing strange ^M characters. Unfortunately, the world's favorite search engine does not do well with special characters in queries, so I'm asking here: What is ...
21
votes
3answers
6k views

Understanding Unix file name encoding

I have a hard time understanding how the file name encoding works. On unix.SE I find contradicting explanations. File names are stored as characters To quote another answer: Several questions about ...
20
votes
5answers
1k views

How can I find the common name for a particular glyph?

Sometimes, I'd like to know the name of a glyph. For example, if I see −, I may want to know if it's a hyphen -, an en-dash –, an em-dash —, or a minus symbol −. Is there a way that I can copy-paste ...
16
votes
2answers
1k views

What does CTRL+4 (and CTRL+\) do in bash?

I just found out by accident that CTRL + 4 closes programs reading stdin input from the command-line. This is how it looks when I type CTRL + 4 or CTRL + / into programs reading stdin ryvnf:~$ ...
12
votes
6answers
3k views

how to type “smart quotes” (U+201C, U+201D)

It's like this: “ (U+201C) ” (U+201D).
11
votes
7answers
4k views

What is the symbol *.* called?

What's the name for the *.* symbol and what is its significance?
11
votes
3answers
26k views

How do I put a hat on 'e' (ê)?

Since I've migrated to linux a few years ago, one issue still remains. The ê character features a lot in my "moeder taal" (home language). In Windows making the character was easy, I simply had to ...
11
votes
2answers
11k views

What does the tilde (~) mean at the end of a filename? [duplicate]

What is the file with the ~ at the end of the filename for? $ ls # aliased to add flags -rwxrwxr-x 1 durrantm 2741 May 16 09:28 strip_out_rspec_prep_cmds.sh~* drwxrwxr-x 13 durrantm 4096 May 16 ...
10
votes
2answers
20k views

What does ^d mean in ls -l | grep ^d?

When I do ls -l | grep ^d it lists only directories in the current directory. What I'd like to know is what does the caret ^ in ^d mean?
10
votes
4answers
4k views

How do I type the degree symbol under X11 (using a default English keyboard layout)?

I'm trying to put in an email the temperature outside in degrees. On my Mac, the degree symbol (°) is Option+Shift+8. But I'm writing the email in Thunderbird on an Ubuntu 10.10 with the default US ...
10
votes
1answer
141 views

Why is the circumflex/caret character used as a symbol for Ctrl?

I started using the Linux console a long time ago but I never questioned myself about the circumflex aka caret character (^). I'd like to ask why it's used as a replacement for the word Ctrl. I ...
8
votes
2answers
614 views

Command line input while a running script displays strange symbols

If I use the bash shell cli and run some program which doesn't return immediately, then I input some letters (basically typing the next command before noticing the previous didn't finish) and the ...
7
votes
2answers
334 views

Why doesn't `echo abc^H` just print `ab`?

As I recall, ^H means Backspace. I generated it by pressing CTRL+V, CTRL+H. So the ^H should remove the last character, as it is the same as Backspace and it should act just as if I pressed Backspace ...
7
votes
4answers
9k views

How to grep for pipe |

How can I grep for line containing pipe character | or for character >: files content: |this is test where is > this is none now what I need using grep command is grep -iE "<some ...
6
votes
1answer
1k views

How to detect and delete lines containing ˆ@

I have a simple problem: In my file, the are lines containing the string ˆ@ˆ@ˆ@ˆ@ˆ@ˆ@. I just want to delete all lines with this string, using for example the sed or grep commands. And I would like ...
6
votes
2answers
219 views

How many commands can be queued up with control operators?

I have been reading up on control operators, and I was wondering if there was a limit to how many commands you could line up with control operators, such as ||, && and ;. In addition, is ...
6
votes
2answers
496 views

How to display control characters (^C, ^D, ^[, …) differently in the shell

When you type control characters in the shell they get displayed using what is called "caret notation". Escape for example gets written as ^[ in caret notation. I like to customize my bash shell to ...
6
votes
2answers
8k views

special character in filename (\#033OA)

I've got a slight problem with a very stubborn error during an rsync. It's caused by a file with a special character in its filename. There's been others but I could sort that out by doing some ...
5
votes
5answers
649 views

How do I remove a file I accidentally created named $file?

I was working on a shell script and I accidentally created a file with the variable as its name. Now I have $file in my ls output, and cannot remove it. What can I do?
5
votes
5answers
1k views

What are the special characters to print from a script to move the cursor?

I found that by printing \r from a script the cursor moves to the beginning of the line. What character will move the cursor up one line? Where is a list of these special characters? EDIT: Working ...
5
votes
2answers
2k views

Is there a way to find files containing only non-printing characters?

I've got a program that's behaving badly and has created a number of files with only a few non-printing characters. If I were to cat the files, I see nothing (since they are non-printing chars). ...
5
votes
1answer
189 views

using ! character in echo

I am messing with echo and having issues with echo displaying the ! character. I tried this. echo -e "Wake!\nUp! bash: !\n!: event not found Then this # echo "Wake\!\nUp!" Wake\! Up! Well now ...
5
votes
1answer
264 views

Representing/quoting NUL on the command line

Can \0 be used on the command line? Background For testing corner cases in GNU Parallel I was curious whether all characters were correctly quoted on the command line. Most of them are: perl -e ...
5
votes
5answers
266 views

Rename folder with odd characters

I have a folder on my Mac called "␀␀␀␀HFS+ Private Data". I'm trying to delete it but it contains a bunch of odd characters that are choking unlink, rm and mv, making it difficult to remove it and ...
4
votes
2answers
1k views

How can I write a non-breaking space? [closed]

When I write a question, I'd like the space between the final word and the question mark to be non-breaking, and this very sentence is an example of it (this is why it is awkward), how can I do that ? ...
4
votes
1answer
528 views

Difference between ' and " on command line (bash)?

I used to use '' and "" interchangeably on the command line, but I recently noticed that '$HOME/some/dir' is not expanded, while "$HOME/some/dir" is. I searched around a little bit and found that "" ...
4
votes
3answers
2k views

Help Shell script to pass variables to rsync

I'm trying to create a simple wrapper shell script for rsync. When I send file names to my script, rsync can never seem to identify the correct location. The file names have spaces in them. I've tried ...
4
votes
2answers
215 views

Strange encoding in Slackware

I am a student and learning about operating systems, I was modifying a file using vi, when I accidentally did something (I don't remember what) that change the codification/encoding and now this is ...
3
votes
5answers
375 views

How can I get the raw formatting output of commands?

I'd like to know which control sequences are sent to bash by programs to format their outputs. For example, if I dump man less I can discern which parts are bold or underlined. ...
3
votes
2answers
91 views

Relations between control characters, signals and terminal

What are the relations between control characters and signals? Or are they unrelated? Are control characters received by a terminal? After a terminal receives a control character, is the terminal ...
3
votes
2answers
5k views

Search and replace control characters (^@, ^M, ^I…) in vi

I copied this line from /proc/some_proc_id/cmdline in my ubuntu machine, java^@-jar^@/usr/lib/selenium/selenium-server-standalone.jar^@-port^@4444^@-trustAllSSLCertificates^@ Somehow, the space ...
3
votes
2answers
712 views

Hash symbol on a teletype

My issue is a bit unusual, so I want to provide a short background. I was looking at old winners of the International Obfucated C Code Contest, and came across an entry written for the PDP-11 (the ...
3
votes
4answers
2k views

Matlab gets “crazy” after type special characters

I'm using a computer running Ubuntu and I'm connected through ssh to a RedHat machine where I use Matlab in command line mode (matlab -nodesktop). Matlab version is 7.10.0.499 (R2010a). My problem ...
3
votes
1answer
31 views

Replace a control character with another control character

A csv file is being generated with a form feed (\f) character. This makes it hard to read in excel, etc. How can I convert the form feed character into a newline (\n) character? All my searches so ...
3
votes
2answers
591 views

How to skip special / socket files during rsync transfer?

Using the following command. rsync --archive --delete --partial --progress --recursive --no-links --no-devices --quiet source target Using --no-links and --no-devices already. Getting the error ...
3
votes
2answers
47 views

How to interpret ' character in a string passed through SSH

New to BASH and Linux and need some quick help. I have written a quick bash script that asks the user for a username and password from the command line and passes that info to a remote server later ...
3
votes
2answers
50 views

What are these rectangular characters and where is this notation defined

Using Linux (Fedora, specifically) as my primary workstation, I noticed, at times, strange non-printable characters like in the following screenshots (bottom-left in the first image and upper-left in ...
3
votes
2answers
100 views

How can I remove files which contain special characters and Latin-1 characters?

I have 2 files in a directory named App on my Ubuntu mahcine. I want to remove those 2 files completely from that directory, but when I try to remove them using rm -rf, they are not deleted. I can't ...
2
votes
4answers
7k views

sh and grep numbers only

I'm facing a problem and trying to find a solution that works in sh. If I could use bash this code would work: ls /a|grep ^[0-9] Unfortunately this is not the case with sh, and yes I need to use ...
2
votes
2answers
679 views

How to rename filename with ' or ? in file name?

I have a problem renaming a file that I'm not even sure which special characters I have in the file. I'm using CentOS 6 64bit. When I ls the file: Giko Suzo San?e - Ep1.avi but when view it in ...
2
votes
2answers
268 views

Very strange ls > textfile problem when viewing with emacs

I want to list the components of the current working directory in a text file ls -1 > textfile Output looks fine with more. 1010661085645 1010729039145 1010747080245 1010849051345 ...
2
votes
1answer
383 views

What characters TAR doesn't like?

I keep a list of photos burned to dvds for incremental backups but I got into a strange situation where a file was already burned into a dvd but tar keeps saying it's not. Here the steps to reproduce: ...
2
votes
1answer
488 views

What is the ` character or symbol called and what is its significance outside of SE code formatting? [duplicate]

What is the ` character's name and what is its significance outside of SE code formatting because I cannot get it to work? I'm familiar with its use in the Stack Exchange forums used to format code ...
2
votes
2answers
904 views

delete directory with special character in filename

I have these tricky directories that I can't figure out how to delete. If I run ls -ld * I get… drwxrwxr-x 7 user1 taskfmri 2048 Jan 22 15:26 857263 drwxrwx--- 4 user2 ...
2
votes
1answer
317 views

Control character STTY issue

I am changing control character (e.g- ^C) using stty intr ^_ under root privileges. It changes successfully. But when I am closing terminal and opening terminal again to check whether same ...
2
votes
1answer
35 views

Using accents in Vim seamlessly

Very often I need to write text/program in foreign languages that need accents and special characters in vim, but sometimes it is very hard to get that working. What are the best alternatives to ...
2
votes
1answer
332 views

tcsh vs zsh. Escape/control characters

I am having problems running this command to work in zsh: my_command -u something -s X:^0 The command works right away on tcsh, but on zsh I get: zsh: no matches found -s X:^0 This made me ...