Questions tagged [here-document]
The here-document tag has no usage guidance.
230
questions
0
votes
0
answers
206
views
How to use heredoc inside my ssh command
I have a bash script that connects to a remote machine via SSH and runs a series of commands.
It seems that the heredoc within the outer script is not aligning properly, and I keep getting an error.
-...
- 1,857
0
votes
2
answers
62
views
How to pass a script-file to sed as a heredoc?
This converts 'a' to 'A'.
sed 's/a/A/g' <(echo "foobar")
foobAr
This supplies the commands necessary to make each vowel upper-case:
$ cat << EOF
s/a/A/g
s/e/E/g
s/i/I/g
s/o/O/g
s/u/...
- 645
0
votes
1
answer
365
views
How can I supply a heredoc to podman run?
When I run buildah, I typically use a heredoc,
ctr=$(buildah from alpine:3);
buildah run $ctr sh -- <<EOF
apk update;
apk add git;
EOF
buildah commit $ctr heredoc_demo;
However, when I ...
- 29.6k
1
vote
1
answer
766
views
Is it possible to run sudo with HEREDOC?
Edit: Amended examples after @Kusalananda answer. My whole picture is more complex. I need multiple commands and a variable definition)
I can't use su because I'm not root and I don't want to input a ...
- 131
1
vote
1
answer
92
views
How can I concat results in the here document?
I have this script:
while read $item;
do
# Some bash logic here
done <<< "$({ cat /path/to/some/file; echo; })"
Now I want to also use find to find the name of some directories,...
- 629
0
votes
1
answer
38
views
When would someone choose to use a limit string (<<-) instead of format here strings the normal way with <<<?
The - option to mark a here document limit string (<<-LimitString) will suppress leading tabs (but not spaces) in the output.
What I'm wondering is why someone would want to remove the leading ...
- 177
0
votes
1
answer
358
views
Unable to capture exit code of a script ran inside of a heredoc
I was playing around and got stuck while trying to capture the exit code of a script I'm running within a heredoc in a Docker container.
Say I want to run this command to start a Docker container ...
0
votes
1
answer
81
views
looping array inside shell script with a different user using HEREDOC doesnt work
I want to perform the set of actions inside a different user while running my script, so i am using HEREDOC to perform such actions, but no matter alternatives i try, i cannot able to reference my ...
3
votes
2
answers
310
views
Can I use Bash Scripting Logic within Here Document?
I have a list of 50 Linux servers that I need to SSH into and check that a key-value pair configuration parameter within a .conf file is set. I need to check that the key-value pair exists. If the key-...
- 31
0
votes
1
answer
205
views
Why this loop is executed for an empty set?
Create an empty directory, then run this code:
find /empty_directory -mindepth 1 -maxdepth 1 -type d |
while read dir;
do
echo "Simple find: $dir"
done
printf '%s\n' '-----' ...
- 629
0
votes
2
answers
191
views
How to make a script fail when there is an error in here string?
I have a script similar to this:
#!/bin/bash
set -euo pipefail
IFS=$'\n\t'
while read -r l; do
echo "${l}"
done <<< "$(cat input.txt)"
echo Success
The command cat ...
- 103
0
votes
1
answer
457
views
lost variable from bash in yaml gitlab ci
Need help
I am studying bash and gitlab
can't get it to work
gitlab pipeline .gitlab-ci.yml
variables:
var1: test1
var2: test2
stages:
- build
build-job:
stage: build
script:
...
- 95
3
votes
1
answer
671
views
Run a shell script in a console session without saving it to file
I have a question about shell scripting on Linux. I am trying to run this:
$ sh << EOF
#!/bin/sh
function test {
echo test
echo test2
}
test
EOF
The result is:
test
test2
But what if I want ...
- 95
0
votes
1
answer
207
views
Add heredoc (<<) to end of alias within function call
I have an alias which is my psql connection string for a database, let's say the alias is this:
alias GQQ='psql "host=$host user=$redshift_uname dbname=$redshift_dbname port=$port pass word=$...
0
votes
1
answer
467
views
Using heredoc to a character device in bash script. EOF error
The script:
#!/bin/bash
interface=enp4s0
mac_address=$(ip link show $interface | grep ether | awk '{print $2}')
cat > /dev/usb/lp0 <<EOF
SIZE 30 mm,90 mm,CLS,TEXT 200,40,0,90,2,2,"MAC ...
- 466
0
votes
2
answers
100
views
How to create heredocs on RAM instead of disk?
Saving following script in a file:
cat <<EOF | wc -l
$HOME
abc
$(hostname)
EOF
and executing it gives the following error:
$ ./a.sh
./a.sh: line 1: cannot create temp file for here-document: ...
- 2,271
3
votes
1
answer
316
views
How to send heredoc command to background?
I want to send a heredoc command like this one
cat <<EOF
line 1
line 2
EOF
to background. (The actual command is openssl with many lines of input which takes some time to complete).
The command ...
- 345
1
vote
2
answers
337
views
run command with STDIN available as root (but without root-password manual insert) inside a bash script
I want to run command as root inside a bash script.
This command needs to be able to read from STDIN.
I have a root password as a local variable inside bash script and don't want to enter it manually.
...
- 113
0
votes
1
answer
41
views
Unexpand the script before executing for handling here document
Let's consider the following code
#!/bin/bash
var=$(
cat <<-EOF
Foo Bar
EOF
)
echo "${var}"
This works as expected with tabs, i.e the var variable ...
- 4,018
0
votes
1
answer
219
views
using heredoc in case statement for remote ssh host
I have a list of ssh commands to run on remote server, so wrote this snippet.
#!/usr/bin/env bash
echo ''
echo "WOULD YOU LIKE TO PERFORM FILES CLEANUP: "
read choice
case $choice in
yes|...
- 1,899
0
votes
1
answer
178
views
Iterating through a command list using heredoc
This works fine:
$ eval 'echo "1" > ~/Desktop/in/foo'
But not this:
$ while IFS= read _cmd; do eval "$_cmd"; done < <(cat << EOF
'echo "1" > ~/Desktop/...
- 645
0
votes
2
answers
760
views
How to use awk $1 $2 in bash shell?
cat << EOF > test.sh
cat $FILEA $FILEB | sort -k1,1 -k2,2n | mergeBed -i - | awk -F\\t '{print $1 "\t" NR "\t\t" $2 "\t" $3 "\t\t.\t\t" NR}' > ...
1
vote
1
answer
71
views
Here-document with two variables
Trying two variables with a here-document to generate a list of bash scripts. I ran into the problem that I cannot put the two variables into the script properly and the output file (only one file) ...
- 161
4
votes
1
answer
1k
views
sed: replace multi-line block with standard input
Given is input_file:
1
2
START
foo
END
3
Goal is to replace content inside including START ... END block with multi-line content from stdin:
1
2
hello
world
3
What I tried:
sed '/^START$/,/^END$/d;...
- 43
10
votes
5
answers
5k
views
How does "cat << EOF | grep" work in bash?
In this answer to How does "cat << EOF" work in bash? on Stack Overflow, I get the first two points. But I don't get the third point Pass multi-line string to a pipe in Bash
Pass ...
- 547
0
votes
2
answers
266
views
Date command not printing inside Heredoc in linux Shell script
I have a shell script where i want to print date which is inside a heredoc. Below is the code snippet.
echo "This is a text"
echo I want date to print inside heredoc <<EOF
var1=`date`
...
- 1
-1
votes
1
answer
608
views
ssh, heredoc and environment variables [duplicate]
(This is RHEL 8.4, if it matters.)
The echo commands on lines 5 and 7 in this script run on the local host, but the hostname commands on lines 6 and 8 run on the remote host as expected.
Why do lines ...
- 1,016
23
votes
2
answers
7k
views
How do you output a multi-line string that includes slashes and other special characters?
I would like to output this on completion of my bash script.
/\_/\
( o.o )
> ^ <
I have tried the following but all return errors.
echo /\\_/\\\n\( o.o \)\n > ^ <
echo \/\\_\/\\\r\n( o....
- 341
0
votes
1
answer
204
views
Heredoc not working in bash script
I made a bash script that was working in Ubuntu mate but now it won't work in Manjaro. It fails on this method:
#!/bin/bash
dev_block="/dev/sdb"
createPartitions(){
echo "...
- 371
1
vote
0
answers
113
views
Appending Multiple Lines Into a File But Skip If They Already Exist
I deal with a lot of config files when I'm working with Linux and because I like automating the setup process I make good use of creating automated shell scripts.
I want to find a fast and efficient ...
- 57
10
votes
2
answers
2k
views
Bash : how to pass arguments to a heredoc script
Imagine you have a silly script test.sh to which arguments are passed that would look like this:
bash test.sh arg1 arg2 arg3
with test.sh being a silly script that displays its command line:
#!/bin/...
0
votes
3
answers
5k
views
After ssh to remote hosts, grep used inside EOF gives output "No such file or directory"
Scenario:
I have a script to connect to remote hosts and grep specific keyword from a log file. Without using EOF the ssh was getting freezed but when used heredoc (EOF) that issue was gone. All my ...
- 133
2
votes
1
answer
19k
views
warning: here-document at line 2 delimited by end-of-file (wanted `EOF')
I've read a lot here and then but still cannot find how to fix this:
steps.wrap([$class: 'AnsiColorBuildWrapper', 'colorMapName': 'XTerm']) {
steps.withCredentials([steps.usernamePassword(...
- 169
1
vote
1
answer
224
views
Tabs not being removed by heredoc
I'm trying to use heredoc with wget using the following code:
xargs wget <<-EOF
https://example\
.com
EOF
Replit link
(yes, I'm already using tabs as required by heredoc)
But for ...
- 113
0
votes
1
answer
257
views
Bash Script Execute ViM Command is Seemingly Not Interpreting the '$' Command
I'm trying to move a certain ViM command into a Linux Bash script. In ViM the command is
:g/^SOMEWORD$/d
To delete any lines containing only some word and nothing else.
When I move it into a bash ...
4
votes
1
answer
1k
views
Bash script : Cat multiple lines in file containing “$” characters [duplicate]
I'm doing a script to auto-install some stuff including a nginx web server.
I'm creating the nginx conf file like this :
cat >/etc/nginx/sites-available/bookstack.conf <<EOL
server {
listen ...
- 55
0
votes
2
answers
329
views
How to append a Linux command line to file?
I am writing a bash script which will generate a Vagrantfile. The reason that i use a bash script to generate Vagrantfile is to enable my colleague to use a single script in setting up their ...
- 205
1
vote
1
answer
41
views
Why does my program continuously execute when supplying an argument with "<<<"?
I have a compiled COTS program (.exe) that I normally interact with via stdin (manual keyboard inputs). Instead, I'm trying to use the <<< to supply input via string instead.
Normally I call ...
- 13
4
votes
1
answer
282
views
dc and standard input or heredoc with string command?
dc can read command from a file or/and from standard input.
If I want to print user input :
cat essai_dc
[enter a number : ]
n
?
p
dc essai_dc
enter a number : 4
4
Now, if I try with a heredoc :...
- 1,960
3
votes
1
answer
2k
views
Using single quotes inside input of heredocs
I need some help debugging my tcsh script. It uses heredocs. The code:
<pre_setup> <<EOF1
<setup> <<EOF2
<command>
exit 0
EOF2
exit 0
EOF1
The <pre_setup> is ...
- 193
0
votes
1
answer
1k
views
Call for a HereDoc inside a Bash Shell loop?
Regarding this post How to include python script inside a bash script
, I get used to work with python HereDoc.
However, I want to include that python HereDoc inside a for loop, and so, it needs to be ...
- 1
3
votes
1
answer
156
views
Heredoc in subfunction in exported function fails
This works:
#!/bin/bash
foo() {
gen() {
cat <<EOF
bar
EOF
true
}
gen
}
foo
export -f foo
bash -c foo
This fails in the very last line:
#!/bin/bash
foo() {
gen(...
- 34.7k
1
vote
2
answers
778
views
Bash doesn't output here-documents to file
This bash script seems broken:
#!/bin/bash
echo "It prints ok"
cat << 'EOF' > ~/doFoo.sh
echo 'nested script doing Foo'
EOF
echo "It never prints"
cat << '...
- 21
1
vote
0
answers
59
views
"cat << limit_string > filename" vs "cat > filename << limit_string"
When using here documents to write multi-line messages to file, in bash, does it matter in which order we apply the here-document (<<) and output redirect (>) operators?
In other words, is ...
- 111
5
votes
3
answers
3k
views
Is there a way to use HEREDOC for Bash and Zsh, and be able to use arguments?
Bash and Zsh's HEREDOC seems to act like a file, instead of string, and if I hope to do something like
foo() {
ruby << 'EOF'
3.times do
puts "Ruby is getting the ...
- 3,009
1
vote
3
answers
444
views
Variables inside heredoc with multiple files
I have a heredoc with xml content, and I add the content of another file like this:
bar file:
<bar>
$baz
</bar>
the script:
bar=$(cat bar.xml)
# this would be the ideal, of course it ...
- 12.1k
3
votes
1
answer
253
views
Strange behavior of nested heredoc
Sorry if dup. I couldn't find any similar issue here, though.
I accidentally found this strange behavior. Could anyone explain this logic?
Why parsed as 'ABC'?
$ cat repro.sh
bash -s <<-EOS1
...
- 49
1
vote
1
answer
1k
views
Why does read appear to fail silently in my script called from another script?
Let me paint a picture for your. You write some deployment scripts or build scripts or somethings etc. which run commands on the remote to do things like e.g. create users, install/update package etc. ...
- 633
4
votes
0
answers
99
views
${$} working fine in ksh93 but ${$} not working when I use in cat << EOF
I'm executing this in the ksh93 shell.
If I use normally like
~# echo ${$}
1295
but using ${$} in a here-document is not working:
~#cat <<EOF
~#> ${$}
~#> EOF
syntax error: `$' unexpected
...
1
vote
3
answers
701
views
Passing huge amounts of data as input to a shell command
Using a bash shell operated through a pipe (non-interactive), I'm trying to pass huge amounts of data to a shell command. So far, I cannot get it to work reliably.
For example, using a here document, ...
- 101