Glasgow | 25-SDC-July | Sheetal Kharab | Sprint 3 | Implement shell tools

implement-shell-tools/cat/cat.js

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+import { program } from "commander";
+import process from "node:process";
+import { promises as fs } from "node:fs";
+
+program
+    .name("cat")
+    .description("print the content of file")
+    .option("-n, --line-numbers","Number the output lines, starting at 1")
+    .option("-b, --number-nonblank", "Number non-empty output lines, overrides -n")
+    .argument("<paths...>", "The file path(s) to process"); // to support multiple file
+program.parse();
+
+const argv = program.args;
+const options = program.opts();
+if (argv.length === 0) {
+    console.error(`No file paths provided`);// to support more files 
+    process.exit(1);
+}
+
+let lineCounter = 1;
+
+for (const path of argv) {
+    try {
+const content = await fs.readFile(path, "utf-8");
+const lines= content.split(/\r?\n/);
+if (lines.length && lines[lines.length - 1] === '') {//// Remove trailing empty line if it's just from the final newline
+    lines.pop();
+}
+
+if (options.numberNonblank) {
+            lines.forEach((line) => {
+                if (line.trim() === "") {
+                    console.log(""); // Blank line, no number
+                } else {
+                    const lineNumber = String(lineCounter++).padStart(6, " ");
+                    console.log(`${lineNumber}\t${line}`);
+                }
+            });
+
+}else if (options.lineNumbers) {
+    lines.forEach((line) => {
+        const lineNumber = String(lineCounter++).padStart(6, ' ');
+        console.log(`${lineNumber}\t${line}`)
+    });
+
+} else {
+    process.stdout.write(content);
+    if (!content.endsWith('\n')) process.stdout.write('\n');
+        }
+    } catch (err) {
+        console.error(`cat: ${path}: ${err.message}`);
+    }
+}

implement-shell-tools/ls/ls.js

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+import { program } from "commander";
+import { promises as fs } from "node:fs";
+
+program
+  .name("ls")
+  .description("Displays files in a directory")
+  .option("-1, --one", "Display each file on a new line")// for listing one file per line
+  .option("-a, --all", "Include hidden files")
+  .argument("[filepath]", "Directory to list files from (default: current)")
+
+await program.parseAsync();  
+
+const opts = program.opts();
+const args = program.args;
+
+const path = args[0] || "."; //Use current directory if no path provided
+let files ;
+try {
+    files = await fs.readdir(path);
+}catch (err) {
+    console.error(`ls: cannot access '${path}': ${err.message}`);
+    process.exit(1);
+
+}
+
+if (!opts.all) {
+  files = files.filter(file => !file.startsWith("."));// if path not provided use current directory
+}
+
+if (opts.one) {
+  files.forEach(file => console.log(file));
+} else {
+  console.log(files.join(" "));
+}
+

implement-shell-tools/package.json

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+{
+  "type": "module",
+  "dependencies": {
+    "commander": "^14.0.0"
+  }
+}

implement-shell-tools/wc/wc.js

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+import { program } from "commander";
+import { promises as fs } from "node:fs";
+
+program
+  .name("wc")
+  .description("Count lines, words, and bytes in files")
+  .option("-l, --lines", "Only print line counts")
+  .option("-w, --words", "Only print word counts")
+  .option("-c, --bytes", "Only print byte counts")
+  .argument("<files...>", "One or more files to process");
+await program.parseAsync();
+
+const files = program.args;
+const options = program.opts();
+
+function countContent(content){
+    const lines = (content.match(/\n/g) || []).length;
+    const words = content.trim().split(/\s+/).filter(Boolean).length;
+    const bytes = Buffer.byteLength(content, 'utf-8');
+    return {lines, words, bytes};
+}
+
+let totalLines = 0;
+let totalWords = 0;
+let totalBytes = 0;
+
+for(const file of files){
+    try{
+        const content = await fs.readFile(file, "utf-8");
+        const {lines, words, bytes } = countContent(content);
+
+        if (options.lines) {
+            console.log(`${lines} ${file}`);
+        } else if (options.words) {
+            console.log(`${words} ${file}`);
+        }else if (options.bytes) {
+            console.log(`${bytes} ${file}`);
+        }else {
+            console.log(`${lines} ${words} ${bytes} ${file}`);
+        }
+
+        totalLines += lines;
+        totalWords += words;
+        totalBytes += bytes;
+
+    }catch (err) {
+    console.error(`wc: ${file}: ${err.message}`);
+  }
+}
+
+if (files.length > 1) {
+    if (options.lines) {
+        console.log(`${totalLines} total`)//if more then 1 file is
+    }else if (options.words) {
+        console.log(`${totalWords} total`);
+    } else if (options.bytes) {
+        console.log(`${totalBytes} total`);
+    } else {
+        console.log(`${totalLines} ${totalWords} ${totalBytes} total`);
+    }
+}