cli: grrs

Author: lencx

README.md

@@ -402,3 +402,7 @@ rustup doc
 * `Object-Oriented`: Object-oriented programs are made up of objects. An object packages both data and the procedures that operate on that data. The procedures are typically called methods or operations.
 * `Polymorphism`: To many people, polymorphism is synonymous with inheritance. But it’s actually a more general concept that refers to code that can work with data of multiple types. For inheritance, those types are generally subclasses. \
 Rust instead uses generics to abstract over different possible types and trait bounds to impose constraints on what those types must provide. This is sometimes called bounded parametric polymorphism.
+
+## Related Links
+
+* [A closer look at Ownership in Rusts](https://blog.thoughtram.io/ownership-in-rust)

cli/grrs/Cargo.toml

@@ -0,0 +1,10 @@
+[package]
+name = "grrs"
+version = "0.1.0"
+authors = ["lencx <[email protected]>"]
+edition = "2018"
+
+# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
+
+[dependencies]
+structopt = '0.3.12'

cli/grrs/src/main.rs

@@ -0,0 +1,46 @@
+// use std::env;
+use std::fs::{self, File};
+use std::io::{self, BufReader, prelude::*};
+use std::path::Path;
+use structopt::StructOpt;
+
+// Search for a pattern in a file and display the lines that contain it.
+#[derive(StructOpt)]
+struct Cli {
+    /// The pattern to look for
+    pattern: String,
+    /// The path to the file to read
+    #[structopt(parse(from_os_str))]
+    path: std::path::PathBuf,
+}
+
+fn main() {
+    let args = Cli::from_args();
+    if let Ok(lines) = read_line(&args.path) {
+        for line in lines {
+            if let Ok(_line) = line {
+                if _line.contains(&args.pattern) {
+                    println!("{:?}", _line);
+                }
+            }
+        }
+    }
+}
+
+/// @see: https://doc.rust-lang.org/stable/rust-by-example/std_misc/file/read_lines.html
+fn read_line<P>(filename: P) -> io::Result<io::Lines<io::BufReader<File>>>
+where P: AsRef<Path> {
+    let file = File::open(filename)?;
+    Ok(io::BufReader::new(file).lines())
+}
+
+// fn main() {
+//     let args = Cli::from_args();
+//     let mut content = fs::read_to_string(&args.path).expect("could not read file");
+
+//     for line in content.lines() {
+//         if line.contains(&args.pattern) {
+//             println!("{}", line);
+//         }
+//     }
+// }