# Literal Here Doc

When shell encounters the syntax `<< 'delimiter'` or `<< "delimiter"`, it starts creating a multi-line buffer using these rules:

1. A line containing exactly `delimiter` ends the contents
2. Escape sequences are **not** expanded (e.g., `\t` is not translated into a literal `TAB`)
3. Variables are **not** expanded (e.g., `$foo` remains `$foo`)
4. Command substitutions are **not** performed (e.g., `$(date)` and `` `date` `` remain unchanged)

The buffer created is sent as `stdin` to the program of your choice. For example:

```
1 #!/bin/sh
2 cat << 'EOF'
3 $bird $(is) `\t\h\e` ${word}
4 EOF
```

Produces:

```
$bird $(is) `\t\h\e` ${word}
```


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