Practical MCP with FastMCP & LangChain

Heredoc

In this guide, we will make extensive use of heredoc to create files. Heredoc is a way to create multi-line strings in Bash. It's a redirection method that allows you to pass multiple lines of input to a command. Here is an example:

cat <file.txt
Passwords are like underwear:
- You shouldn’t leave them out where people can see them.
- You should change them regularly.
- You shouldn’t loan them out to strangers.
EOF

<is the heredoc delimiter. The heredoc ends when the delimiter is encountered at the beginning of a line. The > operator redirects the output to a file. As a result, when you copy and paste the whole block into your terminal, it will create a file named file.txt with the content:

Passwords are like underwear:
- You shouldn’t leave them out where people can see them.
- You should change them regularly.
- You shouldn’t