Insert multiple lines of text before specific line using Bash

Question

I am trying to insert a few lines of text before a specific line, but keep getting sed errors when I try to add a new line character. My command looks like:

Answer 1

On MacOs I needed a few more things.

• Double backslash after the i
• Empty quotes after the -i to specify no backup file
• Leading backslashes to add leading whitespace
• Trailing double backslashes to add newlines

This code searches for the first instance of in pom.xml and inserts another XML object immediately preceding it, separated by a newline character.

sed -i '' "/\<\/plugins/ i \\
\            \\
\                org.apache.maven.plugins\\
\                maven-source-plugin\\
\                \\
\                    \\
\                        attach-sources\\
\                        \\
\                            jar\\
\                        \\
\                    \\
\                \\
\            \\
" pom.xml