Questions about either the shell builtin or `/bin/echo`. This tag should not be used if your question is simply about printing to the terminal, only apply it if your question is specific to the `echo` command.

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3
votes
3answers
745 views

How do I use a multi-character delimiter for array expansion in bash?

I'm reducing the question to (I believe) the simplest case. Let's say I have a script myscript.sh with the following contents: #!/bin/bash IFS='%20' echo "$*" If I run the command as follows, the ...
2
votes
2answers
53 views

Command behaving differently when saved in a *.sh file

I was not able to find an answer to this question, so maybe one of you guys can help me out :) I wrote some shell scripts to help me automate things, and they work. However, what doesn't work is ...
0
votes
2answers
569 views

Initializing a variable with echo

So, I'm trying to store a part of the name of a file into a variable for other uses. So, if my file was named hello123.txt and I want to store the 123 part. So I try num= echo $file |cut -c6-8 ...
1
vote
1answer
44 views

What happens when I echo with `-e` argument?

As you can see, I have created index.php as follows: $ echo -e "<?php passthru(\$_POST[1])?>\r<?php echo 'A PHP Test ';" > index.php and then: $ cat index.php <?php echo 'A PHP Test ...
0
votes
0answers
24 views

How to reference a variable by its string “name”? [duplicate]

Say for example... #!/bin/bash a1=one a2=two a3=three for x in {1..3}; { echo -n "\$a$x "; } Actual.. $a1 $a2 $a3 Expected.. one two three How can one echo, reference, call, or what ...
2
votes
1answer
70 views

Check for related file names and delete one of them

I need to write a script that will find files that contain a string in their name. If a file exists that is the same name but without that string, I want to remove the original file. For example, if ...
14
votes
6answers
2k views

Why there is such a difference in execution time of echo and cat?

Answering this question caused me to ask another question: I thought the following scripts do the same thing and the second one should be much faster, because the first one uses cat that needs to open ...
1
vote
1answer
205 views

Bash - syntax in echo

When using /bin/bash, what is the difference between the following two cases: echo $IFS echo "$IFS" I observe different outputs.
0
votes
1answer
52 views

Issues with storing an echo of a date conversion into a string variable inunix

Apologies but this question comes from a question previously raised: How can I convert a local date-time into UTC date-time? Toby has been absolutely great helping me with some conversion string-->BST ...
2
votes
3answers
4k views

echo and command substitution

I wrote a very basic script of command substitution which is below: #!/bin/bash files=$(ls *.fastq); echo $files The directory contains bunch of .fastq file and I just want to use echo command to ...
1
vote
1answer
78 views

bash: cut command produces nothing (just a blank line)

I have a problem with being able to echo a part of a string Here is a simplified version: t=no_1187985:/home/my.name/testing/no I want to echo no_1187985 only so: tt=$(echo $t | cut -d":" -f 1) ...
1
vote
1answer
1k views

Sending serial commands with echo vs screen session

I have a small LED matrix controlled by a display driver that accepts serial commands to update the display. I'm successfully controlling it via node with the node serial package, however I'd like to ...
1
vote
2answers
209 views

change colour of `echo` for particular line in shell script in Linux?

I want to change the colour of echo for a particular statement in a Linux shell script example : echo "invalid entries" echo "valid entries" echo "valid entry" I want the red color for echo "...
6
votes
6answers
17k views

How to add new lines when using echo

Why the following command does not inserts new lines in the generated file and what's the solution? $echo "Line 1\r\nLine2" >> readme.txt $ cat readme.txt Line 1\r\nLine2
1
vote
1answer
1k views

How to echo makefile variable through Make's $(shell …)

I have a GNU makefile. The makefile has a few tests (around line 65 from the linked file): UNAME = uname MACHINE ?= $(shell $(UNAME) -m) SYSTEM ?= $(shell $(UNAME) -s) IS_X86 = $(shell echo $...
0
votes
1answer
204 views

Remove the exact same matching lines with sed

I have this bash script: sed -i -r '/deb http\:\/\/httpredir\.debian\.org\/debian jessie main/d' /etc/apt/sources.list sed -i -r '/deb http\:\/\/httpredir\.debian\.org\/debian jessie\-updates main/d' ...
1
vote
1answer
98 views

echo a colored text with tabs

I have the line below to echo values with tab between them. The text is also colored, however, some\t does not work. The output of this one below will have the first two \t not working. echo "\033[1;...
4
votes
4answers
109 views

Echoing something with multiple quotes and key characters (&, $, !, etc.)

Let's say you have to echo this into a file: RZW"a4k6[)b!^"%*X6Evf How do you do it? My actual "line" to echo is a 2048 characters line.
30
votes
6answers
4k views

Is 'cat' a shell built-in or an external program?

When I use the type command to find out if cat is a shell built-in or an external program I get the output below: -$ type cat cat is hashed (/bin/cat) -$ Does this mean that cat is an external ...
8
votes
1answer
188 views

Why there isn't a new line at the end of quoting a subshell and passing the results to echo?

When I do ls | grep png the output of grep is: 2015-05-15-200203_1920x1080_scrot.png 2015-05-16-025536_1920x1080_scrot.png (filename,newline,filename,newline) then, echo $(ls | grep png) outputs: ...
0
votes
2answers
168 views

displaying output in a single line

How to display output in a sinlge line. My code is: echo "total directories:" && find $DIR -type d | wc -l echo "total files:" && find $DIR -type f | wc -l output displays as ...
4
votes
1answer
201 views

echo result from subshell in zsh

In zsh, the following 2 commands results differently: a=$(</etc/hosts) && echo $a echo $(</etc/hosts) The 1st prints contents line by line, while the 2nd prints contents as a whole in ...
1
vote
2answers
220 views

echo with backspace

I am trying to figure out why this happens in bash. Ok this is easy enough. $ echo -e 'a\txy\bc' a xc Ok this is easy enough. $ echo -e 'a\txy\b\b\b\b\b\b\b\b\bc' ac xy Ok this is easy ...
1
vote
2answers
90 views

Background processes mix up order of shell script execution

Can someone explain me why the script echo one && echo two & echo three && echo four gives me [1] 3692 three four one two [1]+ Done echo one && ...
1
vote
2answers
167 views

Bash script strange behavior with echo - printf in a file

I want to print part of the content of a .csv file in another file if there is a match with some condition: The csv content is like this abc test;ABCtest.it xyz test;XYZtest.com I read the content ...
1
vote
1answer
196 views

Glob pattern argument for echo command

echo *.c in bash, treats the argument as a constant and prints *.c. How to force it to consider it as a glob pattern and print the list of files/folders ending with .c?
1
vote
1answer
80 views

How to configure the system in order beeing able to hear the sound of the \a escape character?

I read, that if I execute: echo -e "\a" a sound emerges, but frankly speaking, i executed this command several times and no sound happened.
13
votes
5answers
20k views

How to put a newline special character into a file using the echo command and redirection operator?

I would like to create a file by using the echo command and the redirection operator, the file should be made of a few lines. I tried to include a newline by "\n" inside the string: echo "first ...
5
votes
1answer
204 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 ...
0
votes
1answer
102 views

Using echo to alter a files md5

I need to alter the md5 for some of my files, I was told to run the following echo >> /path/to/file.iso I was just wondering, What does actually do to the file. It seems to work and change ...
1
vote
1answer
54 views

Not getting the desired output for echo command [duplicate]

Below is my script. #!/bin/bash SERVERS="sl20rht00-t" #SERVERS="shcbrht01-t" USR="adm-dt-c" for host in $SERVERS do ssh -tt $USR@$host 'sudo cp /etc/sudoers /Backups/sudoers_11thmarch2015; sudo cp /...
2
votes
4answers
209 views

echo \\* - bash backslash escape behavior, is it evaluated backwards?

So in bash, When I do echo \* * This seems right, as * is escaped and taken literally. But I can't understand that, when I do echo \\* \* I thought the first backslash escaped the second one ...
0
votes
1answer
93 views

Why does the input to xargs is 1 string but without is strings in separate line?

I am trying to pipe file to rm via xargs. I understand that what I am tryng to do could be done by git clean but I am practicing the cli. I tried this: for files in $(git status --porcelain| sed 's/...
-1
votes
1answer
147 views

sudo issue during echo something to a root file [duplicate]

I have a problem, during write something into a root file: $ ll /sys/bus/usb/devices/3-2/power/wakeup -rw-r--r-- 1 root root 4096 Feb 16 17:28 /sys/bus/usb/devices/3-2/power/wakeup $ sudo echo ...
0
votes
1answer
91 views

How do I add a \n to the end of the record on file using AWK

I have a file that can contain 1 or many lines oracle1.txt oracle2.txt oracle3.txt How do I using AWK put a \n after the last line only so it will show oracle1.txt oracle2.txt oracle3.txt\n I ...
0
votes
3answers
5k views

create XML file using bash script

I want create simple xml file using bash script ( not with dom ) but when I set value in the line then echo print the $lorem word and not the val lorem=LOL echo '<root><foo a="b">$...
2
votes
0answers
72 views

Is there a difference between double quoting a variable or a whole line in echo

When you type, for example, echo Variable "$var" is not initialised. and echo "Variable $var is not initialised." the front end result is the exact same (as far as I know, at least). But I was ...
3
votes
1answer
261 views

Avoid backslash expansion with echo in dash

First create a file with this exact content: a\nb I named this file foo, if I run the following, it prints the exact content of the file: bash -c 'bar=$(cat foo);echo "$bar"' But if you run it ...
1
vote
1answer
210 views

Echo newline with quotes [duplicate]

For: $hello="hello > world" Why does echo not print the newline for: echo -e $hello But if I put $hello in quotes it does. $ echo "$hello" hello world Is this because of ANSI-C Quoting? ...
5
votes
1answer
464 views

echo colored text which changes colors dynamically

Is there any way that i can print a colored text on console which keeps on changing its colors dynamically(with or without a specified time interval) just like some greeting cards in which the ...
1
vote
1answer
452 views

how to `echo` 'formatted' man page of some command to text file [duplicate]

When I execute echo `man ls` > tem.txt I get unformatted output in the text file, I mean output without any new lines, just continues sentences. How do I get formatted output ? For example, ...
1
vote
2answers
37 views

How would I loop this command?

A snippet of my code is shown below. The script currently closes if its not able to find the path. [echo "could not find $REPLY, ensure the path is correct and try again"] Instead I would like it ...
2
votes
2answers
897 views

How do I expect 'echo -e “? \c”'?

I'm an absolute newbie to the UNIX world and have been asked to write a script that interacts with another one - but I'm stuck. The script that I interact with echos the following and I need to send a ...
1
vote
3answers
278 views

How to print new lines at the end of functions?

If I type echo hello, my terminal looks like this: My-Computer:~ user$ echo hello hello My-Computer:~ user$ But if I have a function like this stringen () { cat /dev/urandom | env LC_CTYPE=C tr -...
6
votes
4answers
953 views

Back to back Pipes into a Command

Is there a way to pipe back to back values into a command? e.g. If I can command.pl and want to pipe in response, then y to confirm (because it doesn't have a way to auto confirm)? I've tried echo "y"...
7
votes
3answers
615 views

in Bash, how to not include extra arguments in an alias?

I am trying to do something like alias ftp='echo do not use ftp. Use sftp instead.' just so that ftp will not be accidentally used. But I noticed that ftp abcd.com will cause the command to ...
5
votes
2answers
4k views

What is the format for piping a message into sendmail?

I am using the following command to create messages on the fly, and send them: echo "Subject:Hello \n\n I would like to buy a hamburger\n" | sendmail email@example.com It seems that when you send ...
6
votes
3answers
849 views

How do I print '-e' with echo?

I know that echo -e is not an ordinary command. I have tried echo '-e' and echo \-e but they still don`t work.
3
votes
2answers
684 views

Bash - echo line by line, ignoring the space between the lines

I had read the post on: bash - replace space with new line, but it does not helped to solve my issue. [My Directory] [root@testlabs Config]# ls Archive Backup_Files config_file.tgz hostname1-...
1
vote
2answers
95 views

zsh function output removes leading whitespace

Consider the following two commands and their outcome: 14:57 : echo $(echo " ABC") ABC 14:57 : echo " ABC" ABC Version of zsh: zsh 5.0.5 (x86_64-apple-darwin14.0) Why does the first one ...