2 files changed, 76 insertions(+), 12 deletions(-)

D cmd/cal/go.sum
A cmd/head/main.go

@@ 1,12 0,0 @@
-github.com/fatih/color v1.15.0 h1:kOqh6YHBtK8aywxGerMG2Eq3H6Qgoqeo13Bk2Mv/nBs=
-github.com/fatih/color v1.15.0/go.mod h1:0h5ZqXfHYED7Bhv2ZJamyIOUej9KtShiJESRwBDUSsw=
-github.com/mattn/go-colorable v0.1.13 h1:fFA4WZxdEF4tXPZVKMLwD8oUnCTTo08duU7wxecdEvA=
-github.com/mattn/go-colorable v0.1.13/go.mod h1:7S9/ev0klgBDR4GtXTXX8a3vIGJpMovkB8vQcUbaXHg=
-github.com/mattn/go-isatty v0.0.16/go.mod h1:kYGgaQfpe5nmfYZH+SKPsOc2e4SrIfOl2e/yFXSvRLM=
-github.com/mattn/go-isatty v0.0.17 h1:BTarxUcIeDqL27Mc+vyvdWYSL28zpIhv3RoTdsLMPng=
-github.com/mattn/go-isatty v0.0.17/go.mod h1:kYGgaQfpe5nmfYZH+SKPsOc2e4SrIfOl2e/yFXSvRLM=
-golang.org/x/sys v0.0.0-20220811171246-fbc7d0a398ab/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
-golang.org/x/sys v0.9.0 h1:KS/R3tvhPqvJvwcKfnBHJwwthS11LRhmM5D59eEXa0s=
-golang.org/x/sys v0.9.0/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
-golang.org/x/term v0.9.0 h1:GRRCnKYhdQrD8kfRAdQ6Zcw1P0OcELxGLKJvtjVMZ28=
-golang.org/x/term v0.9.0/go.mod h1:M6DEAAIenWoTxdKrOltXcmDY3rSplQUkrvaDU5FcQyo=

@@ 0,0 1,76 @@
+package main
+
+import (
+	"bufio"
+	"flag"
+	"fmt"
+	"io"
+	"os"
+)
+
+func main() {
+	var verbose, silent bool
+	var linecount int
+	flag.BoolVar(&verbose, "v", false, "always print file headers")
+	flag.BoolVar(&silent, "q", false, "never print file headers")
+	flag.IntVar(&linecount, "n", 10, "print the first `NUM` lines;\nwhen negative, print all but the last `NUM` lines")
+	flag.Parse()
+
+	if linecount == 0 {
+		os.Exit(0)
+	}
+
+	pos := linecount > 0
+	if !pos {
+		linecount = -1 * linecount
+	}
+
+	doHead := func(r io.Reader) {
+		lineBuffer := make([]string, linecount)
+		var rIdx, iIdx int
+		scanner := bufio.NewScanner(r)
+		for scanner.Scan() {
+			lineBuffer[iIdx] = scanner.Text()
+			iIdx++
+
+			if pos && iIdx == linecount {
+				break
+			}
+			if iIdx == linecount {
+				iIdx = 0
+			}
+
+			if !pos && rIdx == iIdx {
+				fmt.Println(lineBuffer[rIdx])
+				rIdx++
+			}
+			if rIdx == linecount {
+				rIdx = 0
+			}
+		}
+
+		if pos {
+			for rIdx < iIdx {
+				fmt.Println(lineBuffer[rIdx])
+				rIdx++
+			}
+		}
+	}
+
+	if flag.NArg() > 0 {
+		for _, fname := range flag.Args() {
+			if verbose || (!silent && flag.NArg() > 1) {
+				fmt.Printf("==> %s <==\n", fname)
+			}
+			ifile, ierr := os.Open(fname)
+			if ierr != nil {
+				fmt.Fprintln(os.Stderr, ierr.Error())
+				os.Exit(1)
+			}
+			doHead(ifile)
+			ifile.Close()
+		}
+	} else {
+		doHead(os.Stdin)
+	}
+}