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Questions tagged [here-document]

230 questions
131
votes
3 answers

How do you use output redirection in combination with here-documents and cat?

Let's say I have a script that I want to pipe to another command or redirect to a file (piping to sh for the examples). Assume that I'm using bash. I could do it using echo: echo "touch somefile echo foo > somefile" | sh I could also do almost the…
strugee
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118
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9 answers

Can't indent heredoc to match code block's indentation

If there's a "First World Problems" for scripting, this would be it. I have the following code in a script I'm updating: if [ $diffLines -eq 1 ]; then dateLastChanged=$(stat --format '%y' /.bbdata | awk '{print $1" "$2}' | sed…
Bratchley
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39
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1 answer

passing and setting variables in a heredoc

I have a script that has to do many different things on many different remote machines. I thought that a heredoc would work for this, but I am not able to use a variable defined elsewhere in the script and one defined in the heredoc. Here is some…
trubliphone
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30
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3 answers

How to execute code in a new tmux session - from within current session?

I use Ubuntu 16.04 and I need the following tmux solution because I want to run a timeout process with sleep as in my particular case I wasn't satisfied from at and encountered a bug with nohup (when combining nohup-sleep). Now, tmux seems as best…
user149572
23
votes
2 answers

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.o )\r\n > ^ < echo /\\_/\\\n\( o.o \)\n \> ^ < How do I…
James Geddes
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23
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2 answers

Is it possible to use multiple here-docs in bash?

Can one use multiple here-docs to provide input to a command in bash? $ cat << foo > EOF1 > bar > EOF2 bar Obviously, in both cases, the second here-doc is used as stdin, and replaces the first reference. Is the…
Sparhawk
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22
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1 answer

What does POSIX require for quoted here documents inside command substitution?

In How do I bring HEREDOC text into a shell script variable? someone reports a problem using a here document with a quoted delimiter word inside $(...) command substitution, where a backslash \ at the end of a line inside the document triggers…
Michael Homer
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21
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3 answers

bash script error stty: standard input: Inappropriate ioctl for device

I'm using here-documents in a bash script to automate installation and setup where a password is required many times. I enter the password once and the script passes it to the various commands. In most instances the here-document approach handles…
MountainX
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20
votes
3 answers

Use sudo tee with heredoc to append to existing file

From Generate script in bash and save it to location requiring sudo we have this method, which I like: sudo tee "$OUTFILE" > /dev/null <<'EOF' foo bar EOF However, I would like to use that approach to append to an existing file $OUTFILE. The above…
MountainX
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18
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3 answers

How to combine Bash's process substitution with HERE-document?

In Bash version 4.2.47(1)-release when I try to catenate formatted text that comes from a HERE-dcoument like so: cat <(fmt --width=10 <
Tim Friske
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15
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4 answers

Why is the JSON content from heredoc not parsable?

I have a JSON fragment. The following does not work: VALUE=<
Jim
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14
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3 answers

How to understand "cat > file_name << blah" command?

In following command cat takes the content of here-doc and redirects it to file named conf: cat > conf << EOF var1="cat" var2="dog" var3="hamster" EOF How to understand the order of commands here? Does bash first processes everything else(here-doc…
Martin
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13
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5 answers

Using a here-doc for `sed` and a file

I want to use a here-doc for sed commands and provide the file to be read and the output file. I've looked at Here-Documents from Advanced Bash Scripting guide but it does not mention anything about regular arguments in using a here-doc. Is it even…
Tristian
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13
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2 answers

Passing a variable to a bash script that uses 'EOF' and considers the variable a literal

in this script i end up with "$1" being saved to the /test file. #!/bin/bash cat > /test << 'EOF' $1 EOF the truth is.. i need to keep 'EOF' as 'EOF' because my argument($1) contains dollar signs. but i need that argument to be saved rather than…
user72685
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12
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3 answers

bash: Some issue when using read <<<"$VARIABLE" on a read-only root partition. Any known workarounds?

Just by coincidence I had to use my ATA-ID-to-device-name script (found here: https://serverfault.com/questions/244944/linux-ata-errors-translating-to-a-device-name/426561#426561) on a read-only / partition. In case you're curious, it was an Ubuntu…
syntaxerror
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