cut is now working

cut/.gitignore

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+cut
+cut.exe

cut/Makefile

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+
+
+build:
+	go build .

cut/go.mod

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+module lcthw.dev/go/go-coreutils/cut
+
+go 1.25.3

cut/main.go

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+package main
+
+import (
+  "fmt"
+  "flag"
+  "strings"
+  "log"
+  "strconv"
+  "bufio"
+  "os"
+)
+
+type Opts struct {
+  FieldOpt string
+  Fields []int
+  Delim string
+}
+
+func parse_opts() Opts {
+  var opts Opts
+
+  opts.Fields = make([]int, 0, 10)
+
+  flag.StringVar(&opts.FieldOpt, "f", "", "fields list")
+  flag.StringVar(&opts.Delim, "d", "\t", "delimiter byte")
+  flag.Parse()
+
+  if opts.FieldOpt == "" { log.Fatal("-f fields list required") }
+
+  for _, num := range strings.Split(opts.FieldOpt, ",") {
+    as_int, err := strconv.Atoi(num)
+    if err != nil { log.Fatal("-f can only contain numbers") }
+
+    opts.Fields = append(opts.Fields, as_int)
+  }
+
+  return opts
+}
+
+func main() {
+  opts := parse_opts()
+
+  scan := bufio.NewScanner(os.Stdin)
+  for scan.Scan() {
+    line := scan.Text()
+
+    chopped := strings.Split(line, opts.Delim)
+
+    for i, field_num := range opts.Fields {
+      if field_num >= len(chopped) {
+        fmt.Print("\n")
+        continue
+      }
+
+      fmt.Print(chopped[field_num])
+
+      if i < len(opts.Fields) - 1 {
+        fmt.Print(opts.Delim)
+      } else {
+        fmt.Print("\n")
+      }
+    }
+  }
+}