Questions tagged [read]
`read` is a shell utility used for reading strings from the standard input stream, or from a file descriptor.
355
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reading into variables from "piped" data [duplicate]
I have a csv (Fieldseparator is the ',') file with data in it and I would have to prepare the csv before reading it (mainly just sort it) into variables. How can I read the sorted stream into ...
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1
answer
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prompt in git hook?
I'm trying to implement an option to skip a pre-commit hook (which will be considered pass and perform the commit) in a pre-commit hook.
Everything is running fine except the prompt which reads an ...
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0
answers
49
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Store multiline output in separate variable
A script outputs 3 line output:
$ Filename /a/Resource/.Filename.man.markdown
.Filename.man.markdown
.Filename
man.markdown
What I want to do
I want to store the 3 line output in separate variable, ...
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18
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Kitty shortcut to escape prompt
Inspired by this answer I have the following mapping in my kitty.conf to escape a stuck command quickly:
map ctrl+shift+z send_text normal \x1akill -9 %%\r
But for commands which prompt the user such ...
- 501
3
votes
1
answer
261
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"read -r" builtin in bash script acts differently on Mac
I have this script:
#!/bin/bash
function main {
while read -r file; do
do_something "$file"
done <<< $(find . -type f 2>/dev/null)
}
function do_something{
echo file:$@...
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0
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31
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Why does "read -a" give out error "bad option -a"? [duplicate]
I tried this command :
read -a arr <<< "a b c"
on centos, it runs well, but on kali (2023.2), it reports "read: bad option: -a"
I cannot find out why. Any help please?
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1
answer
21
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how to write a commant for output of a particular group?
Reading file prod1.tpr, VERSION 2019.6 (single precision)
Reading file prod1.tpr, VERSION 2019.6 (single precision)
Select a group of reference atoms and a group of molecules to be ordered:
Group ...
5
votes
1
answer
502
views
Why does sending a trapped signal cause `read` to return in POSIX shell but not in Bash?
I was trying to write a shell script that idly waits for a signal in the background. Since the script doesn't take user input I thought of using read to block the script indefinitely while waiting.
In ...
- 53
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0
answers
84
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Get coordinates with xdotool upon user click and use them in an automation script
I am trying to prompt the user "Click the confirm button" and use the coordinates as a variable in a script.
If the user clicks at 1285 786, I would like to click this coordinate once and ...
2
votes
1
answer
162
views
how to use read -s with printf
If I use "read -s" it deletes the existing line and brings the next prompt to the same line as mentioned below. Please let me know any solution to this error. I need to use "-s" ...
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2
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2
answers
106
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how to specify multiple inputs for a command in shell script
I have several fastq files per sample and all of them should be provided at once as an input (as they all belong to one sample, they should NOT be treated independently like in a for loop, as they are ...
- 1,016
1
vote
1
answer
54
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Why is my entire home backed up?
I wish to back up some of the files located in my home dir.
That is
simple files at the root of my home
and some directories in my home, listed in ~/worthsaving.txt
Sample worthsaving.txt:
cloud
...
0
votes
1
answer
352
views
Can't capture the output of git pull command in a variable
I run git -C /another-directory pull and I get this error:
Your configuration specifies to merge with the ref 'refs/heads/main'
from the remote, but no such ref was fetched.
Now I want to get that ...
- 545
0
votes
1
answer
150
views
How does "done < file" work in a while loop?
While trying to learn how to manipulate the content of files in bash, I encountered the following code example:
while IFS=, read -r col1 col2
do
echo "I got:$col1|$col2"
done < myfile....
- 143
0
votes
1
answer
114
views
Detect whether input is coming from the terminal
I have a shell script that can read from a file or from standard input. Currently, if you don't give it a file or pipe text into it, it starts accepting input at the command prompt.
Instead, I would ...
- 1,822
0
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1
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97
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How to capture subshell exit code when assigning subshell output to read? [duplicate]
Consider:
$ read -r a <<<$(echo "foo"; exit 1)
$ echo $?
0
this returns 0, when I really expect a 1. How can I extract the real exit code from the subshell?
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1
answer
90
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Printing bash read input character to terminal
Does the bash read command always print the user input on terminal or would I print it myself using echo.
For instance I do read -n 1 repl inside a while do loop, reading each character every time.
- 1,183
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0
answers
90
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SSH Connection - Open File to read
im kinda confused,
i tried to establish an connection to my server
function autoban () {
ssh -t xxx.server "sudo su && vi xxx.sh"
}
by this im trying to connect > go ...
- 1
2
votes
0
answers
46
views
Why typing long string into read input with color misbehaves? [duplicate]
I can't seem to move my cursor to the beginning of colored read input when I'm typing a really long string. This below gif shows exactly that, the cursor just stuck on there and I can't move it to ...
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0
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171
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zsh: read line without clearing screen below prompt while allowing user to use arrow keys to make edit in middle of line
Using Bash tput cup 0 0; read -e -p "Enter input: " userinput works well for getting a line of user input:
It does not clear screen below the prompt
It allows user to use arrow keys to go ...
- 566
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0
answers
33
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Distribute subcommands over head command to avoid writing same words twice?
I would like to try to write this command:
while read -r repo; do gh repo delete $repo; done <<< $(gh repo list --no-archived)
which basically cleans up my GitHub and deletes everything that ...
- 143
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1
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120
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How to use two newline characters as delimiter when reading input using read
The following command:
$ read input
hello \
> world
$ echo "$input"
allows me to enter multiline input by using the backslash character.
I'm now looking to change this to allow the ...
- 198
2
votes
1
answer
582
views
How to read multiline input in bash
I have this script:
#!/usr/bin/env bash
main() {
while true; do
read -r -ep "> " input
history -s "$input"
echo "$input"
done
}
main
which works well ...
- 198
-3
votes
2
answers
268
views
Why this program can not read text file in struct? [closed]
Here is my a.txt file which is of three lines. It does not contain any extra spaces or any non printable characters:
David Joans
018976
David12
Here is my code in C to read this file where I have ...
0
votes
1
answer
68
views
How does the Kernel implement synchronisation techniques on file access
I've read that the kernel implements synchronisation mechanisms when accessing files. For example, if we try and write or read to a file in the file system using read() or write() from different ...
- 1,121
0
votes
1
answer
25
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Echo'ing the variable muliple times while reading the variable values from a file
I am trying to write a bash script which would read values from a file and echo out the values. But for what ever reason it is not working correctly.
My first file is having the below values
Alts Risk ...
- 101
0
votes
4
answers
267
views
Read from file; and execute its content line by line; terminate at first error [closed]
I am reading the content of a file do.sh using the bash command line structure. I want to execute each line of this file, line by line, so that, later, I can add some text to the script which can ...
0
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1
answer
61
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How can I reinstall the "read" command? [closed]
About half hour before posting this, I ran the autoclean and autoremove commands.
A few minutes after running the commands, I ran a script that I've been using for months, there are no issues with it.
...
- 85
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votes
1
answer
51
views
Bash readline eats everything if piped
I have a simple script.
# test.sh
read -p ">> " user
read -p ">> " -n1 yes
echo
echo "user: $user"
echo "yes: $yes"
When executed as bash test....
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2
votes
1
answer
187
views
Specify a Keypress as a variable for "if" command
Before continuing, please bear in mind that I am aware that I could configure keyboard shortcuts through the settings menu, but that would not be of use for my end goal.
I'm trying to create a simple ...
- 85
0
votes
1
answer
118
views
Unable to transfer file content via `read` command
I am trying read the contents of file into an array for further processing later. I am using read command for filling the array values. The following is a portion of my code that is causing the error.
...
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1
vote
1
answer
315
views
How to separate long string into a string array with IFS and read, or any other method
I have a long line that comes as output from a git command: a=$(git submodule foreach git status). It looks like this:
a = "Entering 'Dir1/Subdir' On branch master Your branch is up to date with '...
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3
votes
1
answer
239
views
Bash variable truncated when passed into ffmpeg
I have an album of 11 .flac audio files. (edit: since this issue has been resolved, it's now clear that the precise names and content of the files are irrelevant, so I've renamed them):
> find . -...
- 33
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votes
1
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85
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Parse huge amounts of files efficiently
I have a folder that holds hunderds of thousands of files called hp-temps.txt. (There are also tons of subfolders)
The content of these files looks like this for example:
Sensor Location ...
- 111
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votes
4
answers
206
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Bash: interactively enter and save large html block into a variable from the terminal
This is simple
#!/bin/bash
echo "What is your name?"
read name
echo "Your name is: $name"
But what if I don't want to treat a name but a large HTML code block with nested tags and ...
- 111
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votes
1
answer
90
views
Why does the execution of these functions break out of this while loop?
The following script is meant to trim all media files in the current working directory.
#!/usr/bin/bash
trimmer() {
of=$(echo "${if}"|sed -E "s/(\.)([avimp4kvweb]{3,3}$)/\1trimmed\.\...
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1
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62
views
How to "properly" read remote sshd server version with bash
I'm trying to read remote SSHD server version with bash without installing an extra tool :
$ cat < /dev/tcp/x.y.z.t/22
SSH-2.0-OpenSSH_7.2 FreeBSD-20160310
^C
CTRL+C is needed, so I tried to read ...
- 1,991
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votes
0
answers
28
views
Why is my script misbehaving sometimes? [duplicate]
I have created a script that can split an audio file into smaller files via ffmpeg using timestamps, and another script which can take in timestamps & names in batches. My use for this script ...
- 2,011
2
votes
3
answers
1k
views
Trying to find complete string values from one file based on another file using AWK
Hello I have 2 files with the first file containing a few values for example
powershell
vectormaps
JuniperSA
and the second file containing values and and ID
appid uid
SplunkforSnort 340
powershell ...
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0
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97
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Problem with read command while searching txt file line by line
I am trying to do a simple dictionary of words inserted by user which are collected in txt file and then the function to learn them. Words in two different languages are seperated by a chosen ...
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0
votes
1
answer
344
views
Looping through variables which is an output of another command
Hello I am learning Scripting here. I am trying to write a simple script using the 'for' loop.
I have hundreds of folders in a folder called user.
if i run this command i get a list of folders that i ...
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2
votes
2
answers
706
views
Reading from two fifos in Bash
I'm trying to read from two fifos (read from one, if there's no content read from the other, and if there's no content in neither of both try it again later), but it keeps blocking the process (even ...
1
vote
0
answers
220
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How to run input (x|grep y) in command [duplicate]
lets say when I execute command and then grep it for a specific output.
for example: man cat|grep "Written"
This gives the name of the authors.
My problem is I want to do this via read.
here ...
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votes
2
answers
2k
views
Trying to create a while loop to output content of one file to another
I am trying to create a while loop so that it takes content from one file and creates some content on another file. But what i noticed is that it is only creating the last line of the file instead of ...
- 101
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2
answers
4k
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What does the "-d" option of the "read" shell command do when I use it with an empty string as argument?
While I was reading this answer, the author used this command to put the result of a heredoc to a variable:
read -r -d '' VAR <<'EOF'
abc'asdf"
$(dont-execute-this)
foo"bar"''
EOF
...
- 965
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0
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203
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redirected stdin : how to get ALL lines of the incoming request instead of doing multiple "read"
THIS QUESTION IS BASH SCRIPT RELATED... the rest is to explain the context.
context : experimentation : create a simple mini webserver with socat instead of apache.
** the test I'm doing is able to ...
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3
votes
1
answer
76
views
How to sort out the wrong entries in the most simple way depending on the corresponding line in the other file?
I have two files:
In one I have a list of strings, which need to removed if the corresponding line in the other file contains a string "NOPE". If it contains "YES" it stays there. ...
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-1
votes
1
answer
200
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write bash code loop a file line by line that have values, first word as a row and create csv [closed]
i have this sample data
dn; uid=456456456,cn=users,dc=efsfb,dc=org,dc=co;
objectclass; top;
objectclass; person;
objectclass; organizationalPerson;
objectclass; inetOrgPerson;
uid; 456456456;
...
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0
votes
1
answer
623
views
How to read numbers of rows and columns and print in a specific way
I need to make a shell script that will receive a number of rows and a number of columns and then print a word as the number of rows and columns.
For example: 2 rows, 3 columns
expected output:
word ...
- 3
1
vote
1
answer
829
views
Splitting a null separated string
Hereafter are two read statements, one that uses a space as a delimiter, and the other \0. Only the first works. What am I doing wrong with the second?
$ IFS=' '; read first second < <(printf &...
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