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Questions tagged [heredoc]

A Here-document is a special syntax of writing literal strings in sourcecode, used by different programming languages.

A heredoc or Here-Document is a way of writing literal strings in sourcecode. Many languages use heredocs: PHP, Perl, C#...

Although syntax can differ between programming languages, most heredocs start by putting a keyword, and end when the keyword is encountered as the only element on a line (no spaces, tabs or other characters are allowed). Perl example:

my $text = <<KEYWORD; #Any non-reserved word would do
This is some text.
It can contain $othervariables which will be replaced
Unless KEYWORD was between single quotes, in Perl.
KEYWORD
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Creating multiline strings in JavaScript

I have the following code in Ruby. I want to convert this code into JavaScript. What is the equivalent code in JS? text = <<"HERE" This Is A Multiline String HERE
Newy
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How does "cat << EOF" work in bash?

I needed to write a script to enter multi-line input to a program (psql). After a bit of googling, I found the following syntax works: cat << EOF | psql ---params BEGIN; `pg_dump ----something` update table .... statement ...; END; EOF This…
hasen
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How can I write a heredoc to a file in Bash script?

How can I write a here document to a file in Bash script?
Joshua Enfield
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How to assign a heredoc value to a variable in Bash?

I have this multi-line string (quotes included): abc'asdf" $(dont-execute-this) foo"bar"'' How would I assign it to a variable using a heredoc in Bash? I need to preserve newlines. I don't want to escape the characters in the string, that would be…
Neil
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Using variables inside a bash heredoc

I'm trying to interpolate variables inside of a bash heredoc: var=$1 sudo tee "/path/to/outfile" > /dev/null << "EOF" Some text that contains my $var EOF This isn't working as I'd expect ($var is treated literally, not expanded). I need to use sudo…
Jon
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Executing multi-line statements in the one-line command-line

I'm using Python with -c to execute a one-liner loop, i.e.: python -c "for r in range(10): print 'rob'" This works fine. However, if I import a module before the for loop, I get a syntax error: python -c "import sys; for r in range(10): print…
user248237
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What is the advantage of using heredoc in PHP?

What is the advantage of using heredoc in PHP, and can you show an example?
johnlemon
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How to cat <> a file containing code?

I want to print code into a file using cat <>: cat <> brightup.sh !/bin/bash curr=`cat /sys/class/backlight/intel_backlight/actual_brightness` if [ $curr -lt 4477 ]; then curr=$((curr+406)); echo $curr >…
UberNate
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Multiline syntax for piping a heredoc; is this portable?

I'm familiar with this syntax: cmd1 << EOF | cmd2 text EOF but just discovered that bash allows me to write: cmd1 << EOF | text EOF cmd2 (the heredoc is used as input to cmd1, and the output of cmd1 is piped to cmd2). This seems like a very odd…
William Pursell
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How to avoid heredoc expanding variables?

I'm trying to create a script file using substitution string from ENV but want also to prevent some from escaping export PLACEHOLDER1="myPlaceholder1Value" sudo /bin/su -c "cat << EOF >…
TheCodeKiller
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Javascript heredoc

I need something like heredoc in JavaScript. Do you have any ideas for this? I need cross-browser functionality. I found this: heredoc = '\
\ \
'; I think it will work for me.…
VeroLom
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here-document gives 'unexpected end of file' error

I need my script to send an email from terminal. Based on what I've seen here and many other places online, I formatted it like this: /var/mail -s "$SUBJECT" "$EMAIL" << EOF Here's a line of my message! And here's another line! Last line of the…
thnkwthprtls
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Calling PHP functions within HEREDOC strings

In PHP, the HEREDOC string declarations are really useful for outputting a block of html. You can have it parse in variables just by prefixing them with $, but for more complicated syntax (like $var[2][3]), you have to put your expression inside {}…
Doug Kavendek
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How do I remove leading whitespace chars from Ruby HEREDOC?

I'm having a problem with a Ruby heredoc i'm trying to make. It's returning the leading whitespace from each line even though i'm including the - operator, which is supposed to suppress all leading whitespace characters. my method looks like this: …
Chris Drappier
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In PHP, what does "<<<" represent?

For example: $sql = <<
Chrish
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