fix review comments

Cargo.lock

@@ -61,6 +61,7 @@ dependencies = [
  "ansi_term 0.12.1 (registry+https://github.com/rust-lang/crates.io-index)",
  "atty 0.2.14 (registry+https://github.com/rust-lang/crates.io-index)",
  "clap 2.33.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "libc 0.2.67 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
 [[package]]

Cargo.toml

@@ -13,6 +13,7 @@ edition = "2018"
 [dependencies]
 ansi_term = "0.12"
 atty = "0.2"
+libc = "0.2"
 
 [dependencies.clap]
 version = "2"

src/input.rs

@@ -20,14 +20,14 @@ impl<'a> Seek for Input<'a> {
         match *self {
             Input::File(ref mut file) => {
                 let seek_res = file.seek(pos);
-                if let Err(Some(29)) = seek_res.as_ref().map_err(|err| err.raw_os_error()) {
+                if let Err(Some(libc::ESPIPE)) = seek_res.as_ref().map_err(|err| err.raw_os_error())
+                {
                     return Err(io::Error::new(
                         io::ErrorKind::Other,
                         "Using '--seek' is not supported when using a pipe",
                     )
                     .into());
                 };
-                dbg!(&seek_res);
                 seek_res
             }
             Input::Stdin(_) => Err(io::Error::new(