New line in variable

Question

I want to create a config file with a .sh file. I can't figure out how i insert new lines.

The code i already have:

domainconf='<VirtualHost *:80>\n ServerName '$fulldomain'\n DocumentRoot '$fullpath'\n </VirtualHost>'
echo $domainconf > /etc/apache2/sites-available/"$fulldomain".conf

Hugely important to quote your variables. Please read https://unix.stackexchange.com/q/171346/4667 — glenn jackman, Jul 05 '16 at 15:51

Kusalananda · Answer 1 · 2016-07-05T15:15:50.237

5

If all you need to do is to write the configuration to a file, then the following would be more readable, and it does away with the need for a variable:

cat >/etc/apache2/sites-available/"$fulldomain".conf <<END_CONFIG
<VirtualHost *:80>
ServerName '$fulldomain'
DocumentRoot '$fullpath'
</VirtualHost>
END_CONFIG

If you absolutely need the thing in a variable:

conf=$(cat <<END_CONFIG
<VirtualHost *:80>
ServerName '$fulldomain'
DocumentRoot '$fullpath'
</VirtualHost>
END_CONFIG
)

echo "$conf" >/etc/apache2/sites-available/"$fulldomain".conf

edited Jul 05 '16 at 15:15

answered Jul 05 '16 at 14:31

Kusalananda

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Does command substitution need double quoting? – Kevin Jul 05 '16 at 19:36
@Kevin You may quote the command substitution if you wish, but it's not necessary here (because here-document). The important bit is the quoting of `$conf` in `echo "$conf"`. – Kusalananda Jul 06 '16 at 06:02
1

@Kevin I'm actually unsure about it, but since I can't seem to get it to *fail* without quoting (for various odd here-doc contents), I believe it's safe. Please feel free to prove me wrong. – Kusalananda Jul 06 '16 at 06:04
2

@Kevin not when it is the value in an assignment, although otherwise it usually does. Kusalananda: Try `echo $( cat < – dave_thompson_085 Jul 06 '16 at 06:14
@dave_thompson_085 Much appreciated, thanks! – Kusalananda Jul 06 '16 at 06:30

score 2 · Answer 2 · edited Jul 05 '16 at 15:13

2

Just echo with '-e' flag

domainconf='<VirtualHost *:80>\n ServerName '$fulldomain'\n DocumentRoot '$fullpath'\n </VirtualHost>'
echo -e "$domainconf" > /etc/apache2/sites-available/"$fulldomain".conf

edited Jul 05 '16 at 15:13

terdon

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answered Jul 05 '16 at 14:10

Tejas Patel

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2

1

Welcome to Unix & Linux @Patrick! If this answer solved your issue, please take a moment and [accept it](http://unix.stackexchange.com/help/someone-answers) by clicking on the check mark to the left. That will mark the question as answered and is the way thanks are expressed on the Stack Exchange sites. – terdon Jul 05 '16 at 15:12

score 2 · Answer 3 · answered Jul 05 '16 at 14:31

2

Another option is to embed literal newlines in the script:

% cat newl  
blah='x
y
z'

echo "$blah"
% sh newl 
x
y
z
%

Do note the quotes on $blah!

answered Jul 05 '16 at 14:31

thrig

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Quentin Morrier · Answer 4 · 2016-07-05T14:50:11.987

1

Try to replace echo by printf

domainconf='<VirtualHost *:80>\n ServerName '$fulldomain'\n DocumentRoot '$fullpath'\n </VirtualHost>'
printf "$domainconf" > /etc/apache2/sites-available/"$fulldomain".conf

edited Jul 05 '16 at 14:50

answered Jul 05 '16 at 14:42

Quentin Morrier

167
8

`printf` is a pretty good solution, but not the way you've used it (which is no better than `echo`). Try `domfmt='\n ServerName %s\n DocumentRoot %s\n '` followed by `printf "$domfmt" "$fulldomain" "$fullpath" > "/etc/apache2/sites-available/$fulldomain.conf"` – cas Jul 06 '16 at 01:04

New line in variable

4 Answers4