Questions tagged [read]
`read` is a shell utility used for reading strings from the standard input stream, or from a file descriptor.
366
questions
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Linux Bash Script - Yes or No - read answer
little script
#!/bin/sh
cat /dev/urandom | tr -dc 'a-zA-Z0-9' | fold -w 24 | head -n 4
printf 'do you like this? (y/n)? '
read answer
if [ "$answer" != "${answer#[Yy]}" ] ;then
...
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1
answer
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views
Is it possible to read user input with no extra variables?
I want to grep an IP address inside Nginx configuration files.
I want to input the IP address with the read command, but I don't want to store input in an additional variable.
So I want something like:...
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1
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views
Add a numerical value to a variable while reading a file in bash in loop [duplicate]
I have a file with the following values. I am trying to read from the file and add 1096 to the last value and generate the output on screen. My original file looks like this.
agile_prod_toolkit,30
...
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1
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2
answers
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views
Is it possible to read from stderr in a bash script?
I have a bash script like this:
#!/bin/bash
while read -r -a line
do
... parse $line in some way
done
This script is executed by piping the command from another program:
some-random-program | ...
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1
answer
75
views
Find - xargs, for every line open a new shell and execute a command and wait for user to exit that shell
Following works
Task: List all folders that contain file of iname *AlbumArt* that also contain iname *cover*.jpg, and for each of those folder list all jpg files with size
find . -type f -iname '*...
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0
votes
1
answer
33
views
Double backslash disappears when printed in a loop
I have a script that joins together various lists of data fields which then needs to have a few more columns added. The file generated looks like this:
$ cat compiled.csv
"name":"...
- 11
1
vote
1
answer
59
views
Unable to read more than 1024 chars on ZSH + MacOS
Trying to read a long input into a variable from ZSH on MacOS.
echo "URL: "
read URL
input is always truncated to 1024 chars... if I try and type additional chars nothing happens.
...
- 131
0
votes
1
answer
66
views
Issue of read with -u and -k in zsh
I am developing a zsh script that uses read -k.
If I execute my script like this (echo a | myscript), it fails to get input.
Apparently it is due to the fact that -k uses /dev/tty as stdin invariably, ...
- 285
2
votes
3
answers
865
views
Execute copy commands from file
I have a DE_CopyOldToNew.txt file with a whole bunch of copy commands for copying old file names to new file names.
The file contains rows like :
cp /migrationfiles/Company\ Name\ GmbH/2014.138_Old\ ...
- 135
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0
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views
read single line from stdin and write to a file
Is there a way in bash to read a single line from stdin and write directly to a file? Something like:
t="$(mktemp)"
while true
do
[read single line from stdin] > "${t}"
[...
- 449
1
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2
answers
120
views
How do I use a nonstandard file descriptor for reading a file into an array with mapfile?
mapfile -t -u 7 arr < textfile gives me
bash: mapfile: 7: invalid file descriptor: Bad file descriptor
Other, more verbose, methods of reading files line-by-line do allow for such descriptor, e.g.
...
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2
votes
1
answer
490
views
Why does `read` fail saying "read error: 0: Resource temporarily unavailable"?
script
#!/bin/bash --
# record from microphone
rec --channels 1 /tmp/rec.sox trim 0.9 band 4k noiseprof /tmp/noiseprof &&
# convert to mp3
sox /tmp/rec.sox --compression 0.01 /tmp/rec.mp3 ...
- 307
2
votes
2
answers
617
views
pipe the read command?
I'm trying to pipe a string with special characters (e.g. HG@eg3,l'{TT\"C! to another command (termux-clipboard-set) with the read program. It seems that read was designed to create a temporary ...
- 309
0
votes
2
answers
98
views
How to catch newlines in user input
I want to do something with user input to use in grep. Like, instead of
uin="first\nsecond\n"
printf $uin | grep d
which outputs second, I want to have the user input it, like
read uin
...
- 103
0
votes
0
answers
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views
Circular pipe situation
More of an academic/theory question - say I have process A piping into process B:
A | B
normally, the way pipes are designed, is if process A dies, the pipeline will gracefully shutdown. However, if ...
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