Here are my results with JavaScript (node.js v14.15.4) added: Language | Simple | Optimized | Notes ------------- | ------ | --------- | -----

Here are my results with JavaScript (node.js v14.15.4) added: Language | Simple | Optimized | Notes ------------- | ------ | --------- | ----- `wc -w` | 0.17 | 0.16 | `wc` reference; optimized sets `LC_ALL=C` `grep` | 0.53 | 0.54 | `grep` reference; optimized sets `LC_ALL=C` Go | 0.82 | 0.29 | C | 0.83 | 0.20 | Rust B | 1.10 | 0.28 | also by Andrew: bonus and custom hash JavaScript | 1.29 | | no readline JavaScript | 1.81 | | with readline Rust A | 1.55 | 0.30 | by Andrew Gallant Python | 2.14 | 1.17 | Ruby | 3.59 | | AWK | 4.28 | 1.22 | optimized uses `mawk` C++ | 6.68 | 0.83 | "optimized" isn't very optimized Shell | 42.60 | 9.50 | optimized does `LC_ALL=C sort -S 2G` Btw: is there something wrong with my shell? //with readline const rl = require('readline').createInterface(process.stdin); const wordCounter = {}; rl.on('line', (line) => { let words = line.toLowerCase().split(/\s+/).forEach(word => { wordCounter[word] = (wordCounter[word] || 0) + 1; }); }).on('close',() => { let output = Object.entries(wordCounter) .sort(([,countA],[,countB]) => countB - countA) .map(wc => wc.join(" ")) .join("\n"); console.log(output); }); -------------------------------------------- //without readline const wordCounter = {}; let lastChunk = ''; process.stdin.on('data', chunk => { let words = (lastChunk + chunk.toString().toLowerCase()).split(/\s+/); if (!words.length) return; lastChunk = words.pop(); for (let word of words) { if (word) wordCounter[word] = (wordCounter[word] || 0)+1; } }).on('end',() => { if (lastChunk) wordCounter[lastChunk] = (wordCounter[lastChunk] || 0)+1; let output = Object.entries(wordCounter) .sort(([,countA],[,countB]) => countB - countA) .map(wc => wc.join(" ")) .join("\n"); console.log(output); });