The tag has no usage guidance.

learn more… | top users | synonyms

63
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, ...
23
votes
7answers
32k 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 ...
1
vote
1answer
41 views

System is no longer outputting UTF-8 characters

I just had an issue with my server where it responded incredibly slowly, so I forced it to reboot over SSH. When I connected back, I found out my system no longer outputs certain characters correctly. ...
5
votes
1answer
195 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 ...
2
votes
1answer
42 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 ...
1
vote
2answers
50 views

Shell eating `?` characters

This is such a simple question that I'm sure it's been asked somewhere, but I can't find it. My shell, which I have not intentionally set up to do so, seems to eat any words involving question marks: ...
10
votes
1answer
149 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 ...
1
vote
1answer
32 views

Escape >');} < / in sed

In 30 files in 30 directories, I want to find: script>');} < /script> and replace it with: script>');} < /script--> What special characters do I need to escape in the find ...
2
votes
2answers
2k views

Double line box_drawing characters in terminal

This piece of code in wikipedia: $ char=( 6a 6b 6c 6d 6e 71 74 75 76 77 78 ) $ for i in ${char[*]}; do printf "0x$i \x$i \e(0\x$i\e(B\n"; done includes one-line box-drawing characters. Are there ...
0
votes
0answers
27 views

Special characters are not recognized even with UTF-8 in KDE

So, I have Manjaro KDE pre 16 and I have some character encoding issues. Characters like ã á and such are not recognised and are represented by the ? sign. And all programs seem to use this encoding ...
0
votes
0answers
43 views

How to search a log file in Linux and escape special characters like square brackets (i.e. [ and ])

How to search a log file in Linux and escape special characters like square brackets (i.e. [ and ]) Can someone point me in the right direction on this? I less the log file as per below: less ...
0
votes
2answers
67 views

Are periods (“.”) valid characters in file or folder names? [closed]

I would like to name my files and folders according to a specific date, e.g. 03.04.2016. I see I can use them but are there any disadvantages to using periods in files or folder names?
5
votes
5answers
325 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 ...
3
votes
2answers
96 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 ...
1
vote
0answers
31 views

Generating 'ASCII-art' banners with arrows

I recently discovered figlet which generates ASCII-art banners. Joy! ... but, alas, I want a banner with an arrow on it. Now... $ figlet unicode → arrow _ _ //\ ...
0
votes
2answers
48 views

Define string with the characters *, single quote and $

I create bash scripts which get sourced from another "main" script to set up variables needed by the main script. These variables need to be able to contain any character and not have them interpreted ...
1
vote
3answers
73 views

Trim a specific field and replace in Unix Shell Script

I have a file with below data: 5773|2015-11-19|2016418|O|2015-11-06|C|AB1CD|826|826|CDE|2015-11-19|22222222222222222222222222222|ABCD|AB|30 ...
0
votes
1answer
41 views

my home directory appears in my download directory

In my Downloads folder when I run ls I see the home directory, and I don't know why, I want to remove it but I am afraid to remove my home folder. Can anyone tell me how I can just remove the home ...
1
vote
3answers
146 views

Sed command with ' special character [closed]

I am trying to execute the following command from bash shell: sed -i "s/\(update.*\)where /\1 where primary_id = '$primary_id', /" *.php As you see, there is a variable which I am inserting using ...
3
votes
2answers
48 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
55 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 ...
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 ...
0
votes
1answer
30 views

Listing a file with strange characters on DD-WRT embedded Linux

When SSHing into my DD-WRT router (Buffalo WHR-HP-G54) with embedded Linux to browse the DHCP Lease list I get strange characters: ~ # more /tmp/udhcpd.leases x▒_▒▒ ▒▒iPhone-de-Tomaz▒ ...
6
votes
2answers
593 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 ...
3
votes
1answer
33 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 ...
1
vote
1answer
217 views

bash set variable with colon (:) and dash (-) in it (as used by lftp)

so lftp uses some weird shell variables, like the following: xfer:log-file = 1 sftp:connect-program = “ssh -a -x -i keyfile” how would I set these variables? I've tried using set, and env; as well ...
1
vote
2answers
104 views

Makefile shell ignoring sed regexp end of line

I have a folder for various testing of C code, containing many files named *.c. My aim is to have a Makefile search for any filename ending in .c and add the root of that filename to the targets. ...
1
vote
0answers
32 views

“render” textfile with carriage returns (^M) and save output to file

I have a Python CLI program that runs for a long time and has a sort of progressbar, which basically prints some text in the loop without "\n" at the end, at the next iteration it prints "\r" to erase ...
0
votes
3answers
91 views

sed command not replacing a text with newline character

The Unix sed command doesn't recognize a backslash escaped n \n as a newline character. For instance, the command sed "s!,!\n!g" is replacing commas in the input text with the letter n and not a ...
3
votes
2answers
108 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 ...
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 ...
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 ...
0
votes
2answers
212 views

How to catch carriage return / line feed in case statement

I tried the following to no avail and couldn't find any documentation. read Option case $Option in [1] ) echo "1" ;; [2] ) echo "2" ;; [$'\n'] ) echo "LF" ;; [0] ) exit ;; * ) ...
3
votes
5answers
395 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. ...
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:~$ ...
0
votes
2answers
74 views

Putting a single quote in a filename [duplicate]

We can a make a directory named $"dollars"&<>\dogs if we surround it with single quotes like the following mkdir '$"dollars"&<>\dogs' However, what if I want to include a ...
2
votes
2answers
111 views

What other special characters are there?

For filenames, I know that you have to use either a double quotes or a backslash to include a space in your file name. Like mkdir "I like coffee" is the same as mkdir I\ like\ coffee Now when you ...
1
vote
2answers
294 views

How tp Print/echo arrow key in unix - bash, version 3.2.52

How do I print ↑ and ↓ in Unix? Basically I have a script written in bash and I am printing some numbers with whom I want to print arrow keys to show increase/decrease. So how do I literally print ...
3
votes
2answers
6k 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 ...
2
votes
3answers
434 views

Garbage in bash session log file. (using script command)

I tried to log bash session using: js:/var/tmp # script -aqf /var/tmp/out In out file I see, besides output, a lot of garbage. Instead of just whitespaces and new lines I see this, for example: ...
1
vote
3answers
57 views

Order of text jumbled when printing

We run an automated process which changes the data structure in a file, and it has run for about a year without any issues. It has just started failing and I have narrowed the problem down to one of ...
31
votes
5answers
24k 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: ...
1
vote
1answer
170 views

TTY control characters sent to stdin of sh doesn't work

I tried to develop a remote app that launches sh and resends an incoming data there, and found that some special sequences don't work. So, for testing purposes, I launched on my desktop sh, then ...
3
votes
2answers
659 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 ...
0
votes
2answers
94 views

non-breaking space sometimes appears in Geany (my standard text editor)

I use Geany for all my coding, in my linux Mint-MATE install. Occasionally, i have a problem where a non-breaking space (char code 194) is present instead of a normal space character (32). This just ...
0
votes
3answers
6k views

Remove special characters in a text file

I have a text file which contains in each line a sql query. For each line, I need to remove some special characters. Expl: if I have: select * from Users; insert into Users values ...
1
vote
5answers
105 views

keep out line break

I have some files with this structure: 2015-03-25 17:08:17 sysUpTimeInstance 93474;^M 1.ValueforState=2500 I want to replace the line break, and leave the third line with the second line, I mean, ...
0
votes
2answers
599 views

Why can't I kill the shell using the PID obtained from the $$ special variable? [duplicate]

After I have learned that the $$ special variable holds the process number of the shell, I tried too kill the shell by simply: kill , however this did not work, I also tried some variations, but them ...
12
votes
6answers
3k views
1
vote
2answers
457 views

Remove control characters from /var/log/boot.log

I have a script that sends out email to sysadmin group when a server is powered on or off. The email contains dump of some important logs like /var/log/messages, /var/log/secure, /var/log/boot.log . ...