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use std::{
fs::File,
io::{self, BufRead, BufReader, ErrorKind, Write},
path::PathBuf,
};
use scurvy::{
Argument, Scurvy,
formula::{PathFormula, UsizeFormula},
};
pub fn main() {
let args = vec![
Argument::new(&["infile", "ifile"]).arg("path"),
Argument::new(&["line-number", "ln"]).arg("line#"),
Argument::new(&["outfile", "ofile"]).arg("path"),
];
let scurvy = Scurvy::make(args);
if scurvy.should_print_help() {
println!("{HELP_STR}");
return;
}
let input = scurvy.parse_req("infile", PathFormula::new());
let output = scurvy.parse_req("outfile", PathFormula::new());
let line_number = scurvy.parse_req("line-number", UsizeFormula::new().bounds(1..));
if let Err(e) = do_work(input, output, line_number) {
eprintln!("{e}");
std::process::exit(-1);
}
}
fn do_work(input: PathBuf, output: PathBuf, line_number: usize) -> io::Result<()> {
let bufr = BufReader::new(File::open(input)?);
let mut out = File::create(output)?;
match bufr.lines().nth(line_number) {
Some(line) => {
out.write_all((line?).as_bytes())?;
Ok(())
}
None => Err(io::Error::from(ErrorKind::UnexpectedEof)),
}
}
// Tab width is usually eight in terminals. Our max line-length for an options
// name line is 72, the help-text itself is 66
const HELP_STR: &'static str = "\
usage: copyline ifile=<path> ofile=<path> ln=<line#>
ARGUMENTS
infile=<path> | ifile=<path>
Input file path. Where we read the line from
outfile=<path> | ofile=<path>
Output file path. Where we write the line to.
line-number=<line#> | ln=<line#>
The line you want, starting at 1.
";
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