head and tail are working.

head/.gitignore

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

head/Makefile

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

head/go.mod

@@ -0,0 +1,3 @@
+module lcthw.dev/go/go-coreutils/head
+
+go 1.25.3

head/main.go

@@ -0,0 +1,43 @@
+package main
+
+import (
+  "fmt"
+  "bufio"
+  "os"
+  "log"
+  "flag"
+  "io"
+)
+
+func HeadFile(file io.Reader, count int) {
+  scan := bufio.NewScanner(file)
+
+  for cur_line := 0; scan.Scan(); cur_line++ {
+    line := scan.Text()
+
+    if cur_line < count {
+      fmt.Println(line)
+    }
+  }
+
+  if scan.Err() != nil { log.Fatal(scan.Err()) }
+}
+
+func main() {
+  var count int
+
+  flag.IntVar(&count, "n", 10, "number of lines")
+  flag.Parse()
+
+  if flag.NArg() > 0 {
+    files := flag.Args()
+    for _, fname := range files {
+      file, err := os.Open(fname)
+      if err != nil { log.Fatal(err) }
+
+      HeadFile(file, count)
+    }
+  } else {
+    HeadFile(os.Stdin, count)
+  }
+}

tail/.gitignore

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

tail/Makefile

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

tail/go.mod

@@ -0,0 +1,3 @@
+module lcthw.dev/go/go-coreutils/tail
+
+go 1.25.3

tail/main.go

@@ -0,0 +1,47 @@
+package main
+
+import (
+  "fmt"
+  "bufio"
+  "os"
+  "log"
+  "flag"
+  "io"
+)
+
+func TailFile(file io.Reader, count int) {
+  scan := bufio.NewScanner(file)
+  var lines []string
+
+  for scan.Scan() {
+    lines = append(lines, scan.Text())
+  }
+
+  if scan.Err() != nil { log.Fatal(scan.Err()) }
+
+  start := len(lines) - count
+  if start < 0 { start = 0 }
+
+  for line := int(start); line < len(lines); line++ {
+    fmt.Println(lines[line])
+  }
+}
+
+func main() {
+  var count int
+
+  flag.IntVar(&count, "n", 10, "number of lines")
+  flag.Parse()
+
+  if flag.NArg() > 0 {
+    files := flag.Args()
+    for _, fname := range files {
+      file, err := os.Open(fname)
+      if err != nil { log.Fatal(err) }
+
+      TailFile(file, count)
+    }
+  } else {
+    TailFile(os.Stdin, count)
+  }
+}