Disable command substitution in heredoc?

Question

How can I disable command substitution in the EOF heredoc?

#!/bin/bash
executableFile="executableFile.sh"
firstFolder="blablabla"
cat <<EOF >$executableFile
    secondFolder="blablabla2"
    if [ \$(cat something) == "blub" ]; then
        echo $firstFolder
        echo $secondFolder
    fi
EOF

The value in the if clause should be requested when executing the executableFile

I'm curious why you're creating a script from a script. Dynamic script generation is a [code smell](https://en.wikipedia.org/wiki/Code_smell). Can you explain your underlying goal? We can probably suggest a better way to do it with static scripts. — John Kugelman, Jan 26 '21 at 11:53

score 3 · Accepted Answer · answered Jan 26 '21 at 11:48

Quoting 'EOF' will disable all special characters and treat the heredoc literally.

cat <<'EOF' >$executableFile
    secondFolder="blablabla2"
    if [ $(cat something) == "blub" ]; then
        echo $firstFolder
        echo $secondFolder
    fi
EOF

I also recommend double quoting all variable expansions. It's not always necessary, but usually it is and it's just a good habit to get into.

cat <<'EOF' >"$executableFile"
    secondFolder="blablabla2"
    if [ "$(cat something)" == "blub" ]; then
        echo "$firstFolder"
        echo "$secondFolder"
    fi
EOF

Disable command substitution in heredoc?

1 Answers1

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