use std::io::{self, Read}; macro_rules! regex { ($re:expr) => {{ use regex::internal::ExecBuilder; ExecBuilder::new($re).build().unwrap().into_regex() }}; } fn main() { let mut seq = String::with_capacity(50 * (1 << 20)); io::stdin().read_to_string(&mut seq).unwrap(); let ilen = seq.len(); seq = regex!(">[^\n]*\n|\n").replace_all(&seq, "").into_owned(); println!("original: {}, replaced: {}", ilen, seq.len()); }