Glasgow | 25-SDC-July | Prati Amalden | Sprint 3 | Implement shell tools

implement-shell-tools/cat/cat.mjs

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+import { program } from "commander";
+import {promises as fs} from "node:fs";
+
+program
+  .name("cat")
+  .description("read, display, and concatenate text files.")
+  .option("-n", " Number all output lines.")
+  .option("-b", " Number non-blank output lines.")
+  .arguments("<paths...>"); // allow more file paths
+
+program.parse();
+
+const options = program.opts();
+const paths = program.args;
+
+for(const path of paths){
+    let content;
+    try {
+        content = await fs.readFile(path, "utf-8")
+    } catch(err) {
+        console.error(`Error reading file "${path}": ${err.message} `);
+        continue;
+    }
+
+    // split file into lines
+    let lines = content.replace(/\n$/, "").split("\n");
+
+    let lineNum = 1;
+
+    for (const line of lines){
+        if(options.b){
+            if(line.trim() !== ""){
+                console.log(`${lineNum.toString().padStart(5)}  ${line}`)
+                lineNum++;
+            } else {
+                console.log("");
+            }
+        } else if(options.n){
+            console.log(`${lineNum.toString().padStart(5)}  ${line}`)
+            lineNum++;
+        } else{
+            console.log(`${line}`)
+        }
+}
+}

implement-shell-tools/ls/ls.mjs

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+import {program} from "commander";
+import {promises as fs} from "node:fs";
+
+program
+  .name("ls")
+  .description("List all the files in a directory")
+  .option("-a, --all", "Include hidden files")
+  .option("-1", "One entry per line")
+  .argument("[dir]", "directory to list", ".");
+
+program.parse();
+
+const options = program.opts();
+const dir = program.args[0] || ".";
+
+const entries = await fs.readdir(dir, { withFileTypes: true });
+
+const visibleNames = [];
+
+for(const entry of entries){
+    if(!options.all && entry.name.startsWith(".")) continue;    
+    visibleNames.push(entry.name);
+}
+
+if(options["1"]){
+    console.log(visibleNames.join("\n"));
+} else{
+    console.log(visibleNames.join("       "));
+}

implement-shell-tools/package.json

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+{
+  "name": "implement-shell-tools",
+  "version": "1.0.0",
+  "description": "Your task is to re-implement shell tools you have used.",
+  "main": "index.js",
+  "type": "module",
+  "scripts": {
+    "test": "echo \"Error: no test specified\" && exit 1"
+  },
+  "keywords": [],
+  "author": "",
+  "license": "ISC",
+  "dependencies": {
+    "commander": "^14.0.0"
+  }
+}

implement-shell-tools/wc/wc.mjs

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+import { program } from "commander";
+import { promises as fs } from "node:fs";
+
+program
+  .name("wc")
+  .description("Display numbers of line, words, and bytes in each file")
+  .option("-l", "Number of lines")
+  .option("-w", "Number of words")
+  .option("-c", "Number of bytes")
+  .argument("<path...>");
+
+program.parse();
+
+const options = program.opts();
+const paths = program.args;
+
+let totalLines = 0;
+let totalWords = 0;
+let totalBytes = 0;
+
+for(const path of paths){
+    let content;
+    try{
+        content = await fs.readFile(path, "utf-8");
+    } catch (err){
+        console.error(`Error reading file "${path}":`, err.message);
+        continue;
+    }
+
+    const lines = content.replace(/\n$/, "").split("\n");
+
+    const words = content.trim().split(/\s+/); // handles multiple spaces
+    const { size } = await fs.stat(path);
+
+    const lineCount = lines.length;
+    const wordCount = words.length;
+    const byteCount = size;
+
+    totalLines += lineCount;
+    totalWords += wordCount;
+    totalBytes += byteCount;
+
+    if(options.l) {
+        console.log(`\t${lineCount} ${path}`);
+    } else if(options.w) {
+        console.log(`\t${wordCount} ${path}`);
+    } else if(options.c) {
+        console.log(`\t${byteCount} ${path}`)
+    } else {
+        console.log(`\t${lineCount}\t${wordCount}\t${size} ${path}`);
+    }
+
+}
+
+if (paths.length > 1) {
+  if (options.l) {
+    console.log(`\t${totalLines} total`);
+  } else if (options.w) {
+    console.log(`\t${totalWords} total`);
+  } else if (options.c) {
+    console.log(`\t${totalBytes} total`);
+  } else {
+    console.log(`\t${totalLines}\t${totalWords}\t${totalBytes} total`);
+  }
+}