Quick code review and clean up to make them all about the same in style.

cat/main.go

@@ -8,19 +8,13 @@ import (
   "strings"
 )
 
-func Fail(err error, format string, v ...any) {
-  err_format := fmt.Sprintf("ERROR: %v; %s", err, format)
-  log.Printf(err_format, v...)
-  os.Exit(1)
-}
-
 type Opts struct {
   Number bool
   Squeeze bool
   Filenames []string
 }
 
-func parse_opts() (Opts) {
+func ParseOpts() (Opts) {
   var opts Opts
 
   flag.BoolVar(&opts.Number, "n", false, "Number all nonempty output lines, starting with 1")
@@ -38,12 +32,12 @@ func parse_opts() (Opts) {
 }
 
 func main() {
-  opts := parse_opts()
+  opts := ParseOpts()
 
   for _, filename := range opts.Filenames {
     in_file, err := os.ReadFile(filename)
 
-    if err != nil { Fail(err, "cannot open %s:", filename) }
+    if err != nil { log.Fatalf("cannot open %s: %v", filename, err) }
 
     if(opts.Number) {
       count := 1

cut/main.go

@@ -16,7 +16,7 @@ type Opts struct {
   Delim string
 }
 
-func parse_opts() Opts {
+func ParseOpts() Opts {
   var opts Opts
 
   opts.Fields = make([]int, 0, 10)
@@ -38,7 +38,7 @@ func parse_opts() Opts {
 }
 
 func main() {
-  opts := parse_opts()
+  opts := ParseOpts()
 
   scan := bufio.NewScanner(os.Stdin)
   for scan.Scan() {

find/main.go

@@ -12,26 +12,33 @@ import (
 type Opts struct {
   Name string
   Type string
-	Print bool
 }
 
-func main() {
+func ParseOpts() Opts {
   var opts Opts
 
   flag.StringVar(&opts.Name, "name", "", "regex of file")
   flag.StringVar(&opts.Type, "type", "f", "type to find")
   flag.Parse()
 
-	re, err := regexp.Compile(opts.Name)
-	if err != nil { log.Fatal(err) }
-
   if flag.NArg() == 0 {
     log.Fatal("USAGE: find -name <regex> [-type d/f] <dir> [dir dir]")
   }
 
+  return opts
+}
+
+func main() {
+  opts := ParseOpts()
+
+  re, err := regexp.Compile(opts.Name)
+  if err != nil { log.Fatal(err) }
+
   for _, start := range flag.Args() {
     filepath.WalkDir(start, func (path string, d fs.DirEntry, err error) error {
-			if re.MatchString(path) && opts.Print {
+      if err != nil { log.Fatal(err) }
+
+      if re.MatchString(path) {
         if opts.Type == "" {
           fmt.Println(path)
         } else if d.IsDir() && opts.Type == "d" {

grep/main.go

@@ -30,6 +30,7 @@ func ScanInput(input io.Reader, exp string, prefix string) {
 }
 
 func main() {
+  // NOTE: can we avoid flag here since it's just raw args?
   flag.Parse()
 
   args := flag.Args()

ls/main.go

@@ -7,19 +7,30 @@ import (
   "flag"
 )
 
-func main() {
-	var recurse bool
+type Opts struct {
+  Recurse bool
+  Paths []string
+}
 
-	flag.BoolVar(&recurse, "R", false, "recursive listing")
+func ParseOpts() Opts {
+  var opts Opts
+
+  flag.BoolVar(&opts.Recurse, "R", false, "recursive listing")
   flag.Parse()
 
-	paths := flag.Args()
+  opts.Paths = flag.Args()
 
-	if len(paths) == 0 {
-		paths = append(paths, ".")
+  if len(opts.Paths) == 0 {
+    opts.Paths = append(opts.Paths, ".")
   }
 
-	for _, what := range paths {
+  return opts
+}
+
+func main() {
+  opts := ParseOpts()
+
+  for _, what := range opts.Paths {
     if flag.NArg() > 1 {
       fmt.Printf("\n%s:\n", what)
     }
@@ -27,7 +38,7 @@ func main() {
     filepath.WalkDir(what, func (path string, d fs.DirEntry, err error) error {
       if path == what { return nil }
 
-			if d.IsDir() && recurse {
+      if d.IsDir() && opts.Recurse {
         fmt.Printf("\n%s:\n", path)
       } else if d.IsDir() {
         fmt.Printf("%s\n", filepath.Base(path))

numfmt/main.go

@@ -13,16 +13,19 @@ import (
 type Opts struct {
   From string
   To string
+  Numbers []string
 }
 
-func parse_opts() (Opts, []string) {
+func ParseOpts() Opts {
   var opts Opts
 
   flag.StringVar(&opts.From, "from", "", "Convert from")
   flag.StringVar(&opts.To, "to", "", "Convert to")
   flag.Parse()
 
-    return opts, flag.Args()
+  opts.Numbers = flag.Args()
+
+  return opts
 }
 
 func to_si(num string) string {
@@ -55,20 +58,20 @@ func to_si(num string) string {
 }
 
 func main() {
-    opts, nums := parse_opts()
+  opts := ParseOpts()
 
   if opts.From != "" {
     log.Fatal("you should implement this")
   }
 
-    if len(nums) == 0 {
+  if len(opts.Numbers) == 0 {
     scanner := bufio.NewScanner(os.Stdin)
     for scanner.Scan() {
       num := scanner.Text()
       fmt.Println(to_si(num))
     }
   } else {
-        for _, num := range nums {
+    for _, num := range opts.Numbers {
       fmt.Println(to_si(num))
     }
   }

od/main.go

@@ -8,12 +8,6 @@ import (
   "bufio"
 )
 
-func Fail(err error, format string, v ...any) {
-  err_format := fmt.Sprintf("ERROR: %v; %s", err, format)
-  log.Printf(err_format, v...)
-  os.Exit(1)
-}
-
 type Opts struct {
   Width int
   Filenames []string
@@ -22,7 +16,7 @@ type Opts struct {
   Format string
 }
 
-func parse_opts() (Opts) {
+func ParseOpts() (Opts) {
   var opts Opts
 
   flag.IntVar(&opts.Width, "w", 16, "Width of output grid")
@@ -46,12 +40,12 @@ func parse_opts() (Opts) {
 }
 
 func main() {
-  opts := parse_opts()
+  opts := ParseOpts()
 
   for _, filename := range opts.Filenames {
     reader, err := os.Open(filename)
     defer reader.Close()
-    if err != nil { Fail(err, "can't open: %s", filename) }
+    if err != nil { log.Fatalf("can't open: %s: %v", filename, err) }
 
     buf := bufio.NewReader(reader)
     count := buf.Size()

sha512sum/main.go

@@ -12,7 +12,7 @@ type Opts struct {
   Inputs []string
 }
 
-func parse_opts() Opts {
+func ParseOpts() Opts {
   var opts Opts
 
   flag.Parse()
@@ -21,7 +21,7 @@ func parse_opts() Opts {
   return opts
 }
 
-func to_hex(hash [sha512.Size]byte) string {
+func ToHex(hash [sha512.Size]byte) string {
   result := ""
 
   for _, b := range hash {
@@ -32,7 +32,7 @@ func to_hex(hash [sha512.Size]byte) string {
 }
 
 func main() {
-	opts := parse_opts()
+  opts := ParseOpts()
 
   for _, fname := range opts.Inputs {
     in_data, err := os.ReadFile(fname)
@@ -40,6 +40,6 @@ func main() {
 
     hash := sha512.Sum512(in_data)
 
-		fmt.Println(to_hex(hash), fname)
+    fmt.Println(ToHex(hash), fname)
   }
 }

sort/main.go

@@ -15,7 +15,7 @@ type Opts struct {
   Numeric bool
 }
 
-func parse_opts() Opts {
+func ParseOpts() Opts {
   var opts Opts
 
   flag.BoolVar(&opts.IgnoreCase, "f", false, "ignore case")
@@ -26,7 +26,7 @@ func parse_opts() Opts {
   return opts
 }
 
-func numeric_sort(a string, b string) int {
+func NumericSort(a string, b string) int {
   a_int, a_err := strconv.Atoi(a)
   b_int, b_err := strconv.Atoi(b)
 
@@ -37,13 +37,13 @@ func numeric_sort(a string, b string) int {
   }
 }
 
-func ignore_case_sort(a string, b string) int {
+func IgnoreCase(a string, b string) int {
   return strings.Compare(strings.ToLower(a), strings.ToLower(b))
 }
 
 func main() {
   lines := make([]string, 0, 100)
-  opts := parse_opts()
+  opts := ParseOpts()
 
   scan := bufio.NewScanner(os.Stdin)
 
@@ -53,9 +53,9 @@ func main() {
   }
 
   if opts.Numeric {
-    slices.SortFunc(lines, numeric_sort)
+    slices.SortFunc(lines, NumericSort)
   } else if opts.IgnoreCase{
-    slices.SortFunc(lines, ignore_case_sort)
+    slices.SortFunc(lines, IgnoreCase)
   } else {
     slices.Sort(lines)
   }

tail/main.go

@@ -27,21 +27,33 @@ func TailFile(file io.Reader, count int) {
   }
 }
 
-func main() {
-  var count int
+type Opts struct {
+  Count int
+  Files []string
+}
 
-  flag.IntVar(&count, "n", 10, "number of lines")
+func ParseOpts() Opts {
+  var opts Opts
+
+  flag.IntVar(&opts.Count, "n", 10, "number of lines")
   flag.Parse()
 
-  if flag.NArg() > 0 {
-    files := flag.Args()
-    for _, fname := range files {
+  opts.Files = flag.Args()
+
+  return opts
+}
+
+func main() {
+  opts := ParseOpts()
+
+  if len(opts.Files) > 0 {
+    for _, fname := range opts.Files {
       file, err := os.Open(fname)
       if err != nil { log.Fatal(err) }
 
-      TailFile(file, count)
+      TailFile(file, opts.Count)
     }
   } else {
-    TailFile(os.Stdin, count)
+    TailFile(os.Stdin, opts.Count)
   }
 }

uniq/main.go

@@ -7,13 +7,13 @@ import (
   "strings"
   "flag"
 )
+
 type Opts struct {
   IgnoreCase bool
   Count bool
 }
 
-
-func parse_opts() Opts {
+func ParseOpts() Opts {
   var opts Opts
 
   flag.BoolVar(&opts.IgnoreCase, "i", false, "ignore case")
@@ -23,7 +23,7 @@ func parse_opts() Opts {
   return opts
 }
 
-func string_equal(a string, b string, ignore_case bool) bool {
+func StringEqual(a string, b string, ignore_case bool) bool {
   if ignore_case {
     a = strings.ToLower(a)
     b = strings.ToLower(b)
@@ -36,12 +36,12 @@ func main() {
   scan := bufio.NewScanner(os.Stdin)
   seen_line := ""
   seen_count := 0
-  opts := parse_opts()
+  opts := ParseOpts()
 
   for scan.Scan() {
     line := scan.Text()
 
-    if !string_equal(line, seen_line, opts.IgnoreCase) {
+    if !StringEqual(line, seen_line, opts.IgnoreCase) {
       if opts.Count {
         fmt.Print(seen_count, " ")
       }

wc/main.go

@@ -26,7 +26,7 @@ type Counts struct {
 }
 
 
-func parse_opts() (Opts, []string) {
+func ParseOpts() (Opts, []string) {
   var opts Opts
 
   flag.BoolVar(&opts.Bytes, "c", false, "Count bytes")
@@ -48,7 +48,7 @@ func parse_opts() (Opts, []string) {
 }
 
 
-func count_file(opts *Opts, filename string) Counts {
+func CountFile(opts *Opts, filename string) Counts {
   var counts Counts
 
   in_file, err := os.Open(filename)
@@ -104,10 +104,10 @@ func print_count(opts *Opts, count *Counts, file string) {
 }
 
 func main() {
-  opts, files := parse_opts()
+  opts, files := ParseOpts()
 
   for _, file := range files {
-    count := count_file(&opts, file)
+    count := CountFile(&opts, file)
     print_count(&opts, &count, file)
   }
 }