tr is now working.

tr/.gitignore

@@ -0,0 +1,2 @@
+tr
+tr.exe

tr/Makefile

@@ -0,0 +1,4 @@
+
+
+build:
+	go build .

tr/go.mod

@@ -0,0 +1,3 @@
+module lcthw.dev/go/go-coreutils/tr
+
+go 1.24.2

tr/main.go

@@ -0,0 +1,100 @@
+package main
+
+import (
+  "flag"
+  "os"
+  "bufio"
+  "strings"
+  "fmt"
+  "log"
+)
+
+type Opts struct {
+  Compliment bool
+  Delete bool
+  Squeeze bool
+  Truncate bool
+}
+
+type Translator struct {
+  opts Opts
+  TwoArgs bool
+  RuneMap map[rune]rune
+}
+
+func (tr *Translator) ParseOpts() {
+  var from []rune
+  var to []rune
+  tr.RuneMap = make(map[rune]rune)
+  tr.TwoArgs = true
+
+  flag.BoolVar(&tr.opts.Compliment, "c", false, "Use compliment of array1")
+  flag.BoolVar(&tr.opts.Delete, "d", false, "Delete chars in array1")
+  flag.BoolVar(&tr.opts.Squeeze, "s", false, "Squeeze chars in array2")
+  flag.BoolVar(&tr.opts.Truncate, "t", false, "Truncate array1 to array2 length")
+  flag.Parse()
+
+  args := flag.Args()
+
+  if flag.NArg() == 1 {
+    from, to = []rune(args[0]), []rune(args[0])
+    tr.TwoArgs = false
+  } else if flag.NArg() == 2 {
+    from, to = []rune(args[0]), []rune(args[1])
+  } else {
+    log.Fatal("USAGE: tr [-c] [-d] [-s] [-t] <array1> [array2]")
+  }
+
+  for i, ch := range from {
+    tr.RuneMap[ch] = to[i]
+  }
+}
+
+func (tr *Translator) Translate(from rune) rune {
+  if !tr.TwoArgs { log.Fatal("translate requires two args") }
+
+  to, ok := tr.RuneMap[from]
+
+  if ok {
+    return to
+  } else {
+    return from
+  }
+}
+
+func (tr *Translator) Delete(line string) string {
+  result := make([]rune, 0, len(line))
+
+  for _, ch := range []rune(line) {
+    _, ok := tr.RuneMap[ch]
+
+    if !ok {
+      result = append(result, ch)
+    }
+  }
+
+  return string(result)
+}
+
+func (tr *Translator) Process(line string) {
+  if tr.opts.Delete {
+    line = tr.Delete(line)
+  } else {
+    line = strings.Map(tr.Translate, line)
+  }
+
+  fmt.Print(line)
+}
+
+func main() {
+  tr := new(Translator)
+  tr.ParseOpts()
+
+  scan := bufio.NewScanner(os.Stdin)
+
+  for scan.Scan() {
+    line := scan.Text() + "\n"
+
+    tr.Process(line)
+  }
+}

wc/go.mod

@@ -1,3 +1,3 @@
-module MY/wc
+module lcthw.dev/go/go-coreutils/wc
 
 go 1.24.2