What does 2&1 means in the script below?

```
compile "$i" "${i%.txt}".ass 2&1
```

Question

What does 2>&1 means in the script below?
```
compile "$i" > "${i%.txt}".ass 2>&1
```

Accepted Answer

it redirects error output to standard output

Answer

it redirects the standard output to the error output

Answer

it simplifies the transition from standard input to standard output

Answer

it links the standard input to the error output

Question from the Bash - Fundamentals test