How to insert \n within a string

I'm generating a private key, this key is for demonstrable purposes only: $ openssl genrsa -----BEGIN RSA PRIVATE KEY----- MIIEogIBAAKCAQEAvB8fZFRS83Kztend5KO9cnWXaqLWot0qLDeLcS8ly718FUdm 3VcCY5j737zz4iwmFf3b20Q2XxlbYC/M13wTJzHBf2d1mRDlpZq7CgX/JSEUW/Hr uXiF6PI+ypkvskyoQcz04rlT8skd7tanXhXINnLwW7gCiNlxQQFkrpfO8Fkh+vYL ... Ewac3GAh9CiMikQEYNxpsuLLboS4NcaQWiGB+1imtPtbp8Gf89pJSVBDubgza2Bb rucNxP3HZtPd6G9CvkMJREYL7jHkXYa5DBzs9LB9mLB4b5H/6KN/fsfj -----END RSA PRIVATE KEY----- There is a newline \n at the end of each of these lines that needs removing, I want everything on a single line so I can set it to an env var. Note: I'm unable to store a multiline env var in .env as docker-compose doesn't support it. I've stripped out all the new lines with this: $(openssl genrsa | tr -d '\n') -----BEGIN RSA PRIVATE KEY-----MII...-----END RSA PRIVATE KEY----- I then manually insert two newlines \n which I'm looking to automate through a script (hence this post). If I don't do this the signing of the JWT fails. -----BEGIN RSA PRIVATE KEY-----\nMII...\n-----END RSA PRIVATE KEY----- I define it within a .env file JWT_PRIVATE_KEY=-----BEGIN RSA PRIVATE KEY-----\nMII...\n-----END RSA PRIVATE KEY----- With node and [dotenv](https://www.npmjs.com/package/dotenv) I access it like so: privateRsaKey = process.env.JWT_PRIVATE_KEY.replace(/\\n/gm, '\n'), Now privateRsaKey looks like this: -----BEGIN RSA PRIVATE KEY----- MII... -----END RSA PRIVATE KEY----- Now I actually use the private key to sign a [JWT](https://www.npmjs.com/package/jsonwebtoken) const signed = jwt.sign(payload, privateRsaKey, { algorithm: 'RS256', ... }); All of the above is working as expected when I bring up the Docker containers. **I need help in the scripting so I don't have to manually insert two \n** Thank you all for you help and patience it's much appreciated.