\n in variable in heredoc

bash variables escaping heredoc
Kamil Roman picture Kamil Roman · Jan 22, 2015 · Viewed 11.1k times · Source

Is there any way to for a Bash heredoc to interpret '\n\' in a heredoc?

I have an iteratively built string in a loop, something like

for i in word1 word2 word3
do
        TMP_VAR=$i
        ret="$ret\n$TMP_VAR"
done

and then I want to use the created string in a heredoc:

cat <<EOF > myfile
HEADER
==
$ret
==
TRAILER
EOF

however I would like to interpret the "\n" character as newline, so that the output is

HEADER
==
word1
word2
word3
==
TRAILER

instead of

HEADER
==
\nword1\nword2\nword3
==
TRAILER

Is it possible? Or should I perhaps build my initial string somehow otherwise?

Answer

Tom Fenech picture Tom Fenech · Jan 22, 2015

In bash you can use $'\n' to add a newline to a string:

ret="$ret"$'\n'"$TMP_VAR"

You can also use += to append to a string:

ret+=$'\n'"$TMP_VAR"

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