$ cargo run -- the poem.txt
   Compiling minigrep v0.1.0 (file:///projects/minigrep)
warning: unused `Result` that must be used
  --> src/main.rs:19:5
   |
19 |     run(config);
   |     ^^^^^^^^^^^
   |
   = note: this `Result` may be an `Err` variant, which should be handled
   = note: `#[warn(unused_must_use)]` on by default
help: use `let _ = ...` to ignore the resulting value
   |
19 |     let _ = run(config);
   |     +++++++

warning: `minigrep` (bin "minigrep") generated 1 warning
    Finished `dev` profile [unoptimized + debuginfo] target(s) in 0.71s
     Running `target/debug/minigrep the poem.txt`
Searching for the
In file poem.txt
With text:
I'm nobody! Who are you?
Are you nobody, too?
Then there's a pair of us - don't tell!
They'd banish us, you know.

How dreary to be somebody!
How public, like a frog
To tell your name the livelong day
To an admiring bog!