init

cmd/cat.go

@@ -0,0 +1,18 @@
+package cmd
+
+import (
+	"gosh/types"
+	"os"
+
+	"github.com/fatih/color"
+)
+
+func GoshCat(sh *types.Shell, filename string) types.CmdOutput {
+	data, err := os.ReadFile(filename)
+	red := color.New(color.FgRed).SprintFunc()
+	if err != nil {
+		return types.CmdOutput{Id: 1, Output: red(err)}
+	}
+
+	return types.CmdOutput{Id: 0, Output: string(data)}
+}

cmd/cd.go

@@ -0,0 +1,22 @@
+package cmd
+
+import (
+	"os"
+
+	"gosh/types"
+
+	"github.com/fatih/color"
+)
+
+func GoshCd(sh *types.Shell, dir string) types.CmdOutput {
+	err := os.Chdir(dir)
+	red := color.New(color.FgRed).SprintFunc()
+	if err != nil {
+		return types.CmdOutput{Id: 1, Output: red(err)}
+	}
+
+	dir, _ = os.Getwd()
+	sh.Cd = dir
+
+	return types.CmdOutput{Id: 0, Output: ""}
+}

cmd/clear.go

@@ -0,0 +1,7 @@
+package cmd
+
+import "fmt"
+
+func GoshClear() {
+	fmt.Print("\033[H\033[2J")
+}

cmd/grep.go

@@ -0,0 +1,60 @@
+package cmd
+
+import (
+	"gosh/types"
+	"regexp"
+	"strconv"
+	"strings"
+
+	"github.com/fatih/color"
+)
+
+func GoshGrep(sh *types.Shell, args map[string]string, input string, regex string) types.CmdOutput {
+	re := regexp.MustCompile(regex)
+	lines := strings.Split(input, "\n")
+
+	red := color.New(color.FgRed).SprintFunc()
+
+	value, ok := args["-C"]
+	var err error
+	context_lines := 0
+
+	if ok {
+		context_lines, err = strconv.Atoi(value)
+		if err != nil {
+			return types.CmdOutput{Id: 1, Output: red(err)}
+		}
+		context_lines++
+	}
+
+	var output strings.Builder
+	for i, line := range lines {
+		if re.MatchString(line) {
+			// Print behind
+			if context_lines != 0 {
+				for bi := i - context_lines; bi < i; bi++ {
+					if bi < 0 {
+						continue
+					} else {
+						output.WriteString(lines[bi] + "\n")
+					}
+				}
+			}
+
+			output.WriteString(line + "\n")
+
+			// Print after
+			if context_lines != 0 {
+				for ai := i + 1; ai < i+context_lines; ai++ {
+					if ai > len(lines)-1 {
+						continue
+					} else {
+						output.WriteString(lines[ai] + "\n")
+					}
+				}
+			}
+		}
+	}
+
+	return types.CmdOutput{Id: 0, Output: output.String()}
+}

cmd/ls.go

@@ -0,0 +1,28 @@
+package cmd
+
+import (
+	"gosh/types"
+	"os"
+	"strings"
+
+	"github.com/fatih/color"
+)
+
+func GoshLs(sh *types.Shell) types.CmdOutput {
+	children, err := os.ReadDir(sh.Cd)
+	red := color.New(color.FgRed).SprintFunc()
+	if err != nil {
+		return types.CmdOutput{Id: 1, Output: red(err)}
+	}
+
+	var output strings.Builder
+	for _, child := range children {
+		if child.IsDir() {
+			output.WriteString(color.CyanString(child.Name()+"/") + "\n")
+		} else {
+			output.WriteString(child.Name() + "\n")
+		}
+	}
+
+	return types.CmdOutput{Id: 0, Output: output.String()}
+}

cmd/pwd.go

@@ -0,0 +1,9 @@
+package cmd
+
+import (
+	"gosh/types"
+)
+
+func GoshPwd(sh *types.Shell) types.CmdOutput {
+	return types.CmdOutput{Id: 0, Output: sh.Cd}
+}

go.mod

@@ -0,0 +1,10 @@
+module gosh
+
+go 1.21.5
+
+require (
+	github.com/fatih/color v1.18.0 // indirect
+	github.com/mattn/go-colorable v0.1.13 // indirect
+	github.com/mattn/go-isatty v0.0.20 // indirect
+	golang.org/x/sys v0.25.0 // indirect
+)

go.sum

@@ -0,0 +1,11 @@
+github.com/fatih/color v1.18.0 h1:S8gINlzdQ840/4pfAwic/ZE0djQEH3wM94VfqLTZcOM=
+github.com/fatih/color v1.18.0/go.mod h1:4FelSpRwEGDpQ12mAdzqdOukCy4u8WUtOY6lkT/6HfU=
+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 v0.0.20 h1:xfD0iDuEKnDkl03q4limB+vH+GxLEtL/jb4xVJSWWEY=
+github.com/mattn/go-isatty v0.0.20/go.mod h1:W+V8PltTTMOvKvAeJH7IuucS94S2C6jfK/D7dTCTo3Y=
+golang.org/x/sys v0.0.0-20220811171246-fbc7d0a398ab/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
+golang.org/x/sys v0.6.0/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
+golang.org/x/sys v0.25.0 h1:r+8e+loiHxRqhXVl6ML1nO3l1+oFoWbnlu2Ehimmi34=
+golang.org/x/sys v0.25.0/go.mod h1:/VUhepiaJMQUp4+oa/7Zr1D23ma6VTLIYjOOTFZPUcA=

main.go

@@ -0,0 +1,126 @@
+package main
+
+import (
+	"bufio"
+	"fmt"
+	"gosh/cmd"
+	"gosh/types"
+	"os"
+	"strings"
+
+	"github.com/fatih/color"
+)
+
+func gosh_print_output(cmdo types.CmdOutput) {
+	switch cmdo.Id {
+	case 0:
+		fmt.Printf(cmdo.Output)
+	case 1:
+		fmt.Printf("Error: %s\n", cmdo.Output)
+	}
+}
+
+func parse_flags(parts []string) (map[string]string, []string) {
+	flags := make(map[string]string)
+	args := []string{}
+	i := 0
+	for i < len(parts) {
+		if strings.HasPrefix(parts[i], "-") {
+			key := parts[i]
+			val := ""
+			if i+1 < len(parts) && !strings.HasPrefix(parts[i+1], "-") {
+				val = parts[i+1]
+				i++
+			}
+			flags[key] = val
+		} else {
+			args = append(args, parts[i])
+		}
+		i++
+	}
+	return flags, args
+}
+
+func gosh_process_input(sh *types.Shell, input string) {
+	// Split by pipe and trim spaces
+	commands := strings.Split(input, "|")
+	var prevOutput types.CmdOutput
+
+	for _, cmdStr := range commands {
+		cmdStr = strings.TrimSpace(cmdStr)
+		parts := strings.Fields(cmdStr)
+		if len(parts) == 0 {
+			continue
+		}
+
+		switch parts[0] {
+		case "pwd":
+			prevOutput = cmd.GoshPwd(sh)
+		case "cd":
+			if len(parts) < 2 {
+				fmt.Println("Usage: cd <dir>")
+				return
+			}
+			prevOutput = cmd.GoshCd(sh, parts[1])
+		case "ls":
+			prevOutput = cmd.GoshLs(sh)
+		case "cat":
+			if len(parts) < 2 {
+				fmt.Println("Usage: cat <path to file>")
+				return
+			}
+			prevOutput = cmd.GoshCat(sh, parts[1])
+		case "grep":
+			if len(parts) < 2 {
+				fmt.Println("Usage: grep <pattern>")
+				return
+			}
+
+			flags, args := parse_flags(parts)
+
+			// Feed previous output to grep
+			prevOutput = cmd.GoshGrep(sh, flags, prevOutput.Output, args[len(args)-1])
+		case "clear":
+			cmd.GoshClear()
+		default:
+			fmt.Println("Unknown command: ", parts[0])
+			return
+		}
+	}
+
+	gosh_print_output(prevOutput)
+}
+
+func main() {
+	reader := bufio.NewReader(os.Stdin)
+
+	c := color.New(color.FgCyan)
+
+	dir, _ := os.Getwd()
+	sh := types.Shell{Cd: dir}
+
+	var should_exit = false
+	for {
+		c.Print(sh.Cd)
+		fmt.Print("> ")
+
+		input, err := reader.ReadString('\n')
+
+		if err != nil {
+			fmt.Println("Error reading input: ", err)
+		}
+
+		input = strings.TrimSpace(input)
+
+		switch input {
+		case "exit":
+			should_exit = true
+		default:
+			gosh_process_input(&sh, input)
+		}
+
+		if should_exit {
+			break
+		}
+	}
+}

readme.md

@@ -0,0 +1,7 @@
+# GoLSh
+
+Go Lang Shell
+
+## Commands
+
+`cd`, `ls`, `pwd`, `grep`, `cat`, `clear`

types/shell.go

@@ -0,0 +1,10 @@
+package types
+
+type Shell struct {
+	Cd string
+}
+
+type CmdOutput struct {
+	Id     int
+	Output string
+}