Update man to add the manual guide

packages/bare-os-coreutils/src/tr.js

@@ -0,0 +1,33 @@
+async function run(ctx, argv) {
+  let del = false
+  const sets = []
+  for (let i = 1; i < argv.length; i++) {
+    if (argv[i] === '-d' || argv[i] === '--delete') del = true
+    else if (argv[i] !== '--') sets.push(argv[i])
+  }
+  if (!sets.length || (!del && sets.length < 2)) {
+    ctx.console.error('usage: tr [-d] SET1 [SET2]')
+    ctx.exitCode = 1
+    return
+  }
+  const s = bareStdin(ctx)
+  if (del) {
+    const kill = new Set(sets[0].split(''))
+    let o = ''
+    for (const ch of s) if (!kill.has(ch)) o += ch
+    ctx.console.log(o)
+    return
+  }
+  const from = sets[0]
+  const to = sets[1]
+  const map = Object.create(null)
+  const n = Math.max(from.length, to.length)
+  for (let i = 0; i < n; i++) {
+    const fc = from[i] || from[from.length - 1]
+    const tc = to[i] != null ? to[i] : to[to.length - 1] || ''
+    map[fc] = tc
+  }
+  let o = ''
+  for (const ch of s) o += map[ch] != null ? map[ch] : ch
+  ctx.console.log(o)
+}