implemented tail and fixed errors in input parser when there is a spacebar but no argument and when there is a arg with len 1

command/command.go

@@ -12,6 +12,7 @@ import (
 	"bbash/command/mv"
 	"bbash/command/pwd"
 	"bbash/command/rm"
+	"bbash/command/tail"
 	"bbash/command/touch"
 	"bbash/environment"
 	"bbash/input_parser"
@@ -56,6 +57,8 @@ func Run_command(in input_parser.Input, env *environment.Env) {
 		mv.Mv(in, env)
 	case "help":
 		help.Help(in, env)
+	case "tail":
+		tail.Tail(in, env)
 	default:
 		if !run_by_path(in, env) {
 			fmt.Println(fmt.Sprintf("No such command! (%s)", in.Instruction))

command/man/man.go

@@ -8,30 +8,31 @@ import (
 
 func Man(in input_parser.Input, env *environment.Env) {
 	switch in.Args_raw {
-		case "pwd":
-			fmt.Print("Output current working directory")
-		case "echo":
-			fmt.Print("Echoes the input argument")
-		case "ls":
-			fmt.Print("List Sources in the current working directory")
-		case "cd":
-			fmt.Print("Change to directory given in the argument")
-		case "man":
-			fmt.Print("Manual for the terminal options")
-		case "cat":
-			fmt.Print("Outputs the contents of the given file")
-		case "head":
-			fmt.Print("Outputs first lines of a given file. 10 if non provided. Argument <file> <number of lines>")
-		case "touch":
-			fmt.Print("Creates the given file")
-		case "rm":
-			fmt.Print("Removes the given file")
-		case "cp":
-			fmt.Print("Copies the given file. Argument: <source> <destination>")
-		case "mv":
-			fmt.Print("Moves a given file. Argument: <source> <destination>")
-		default: fmt.Println(fmt.Sprintf("No such command! (%s)", in.Instruction))
+	case "pwd":
+		fmt.Print("Output current working directory")
+	case "echo":
+		fmt.Print("Echoes the input argument")
+	case "ls":
+		fmt.Print("List Sources in the current working directory")
+	case "cd":
+		fmt.Print("Change to directory given in the argument")
+	case "man":
+		fmt.Print("Manual for the terminal options")
+	case "cat":
+		fmt.Print("Outputs the contents of the given file")
+	case "head":
+		fmt.Print("Outputs first lines of a given file. 10 if none provided. Argument <file> <number of lines>")
+	case "touch":
+		fmt.Print("Creates the given file")
+	case "rm":
+		fmt.Print("Removes the given file")
+	case "cp":
+		fmt.Print("Copies the given file. Argument: <source> <destination>")
+	case "mv":
+		fmt.Print("Moves a given file. Argument: <source> <destination>")
+	case "tail":
+		fmt.Print("Outputs last lines of a given file. 10 if none or 0 is provided. Argument <file> <number of lines>")
+	default:
+		fmt.Println(fmt.Sprintf("No such command! (%s)", in.Instruction))
 	}
 }
-
-

command/tail/tail.go

@@ -0,0 +1,84 @@
+package tail
+
+import (
+	"bbash/environment"
+	"bbash/input_parser"
+	"bufio"
+	"bytes"
+	"fmt"
+	"io"
+	"os"
+	"strconv"
+	"strings"
+)
+
+func Tail(in input_parser.Input, env *environment.Env) {
+	args := in.Args
+	var file_path string
+	var lines int
+	if len(args) >= 1 {
+		file_path = strings.TrimSpace(args[0])
+	} else {
+		fmt.Print(fmt.Sprintf("No arguments provided"))
+		return
+	}
+	if len(args) == 2 {
+		lines1, err := strconv.Atoi(strings.TrimSpace(args[1]))
+		lines = lines1
+		if err != nil {
+			fmt.Print(fmt.Sprintf("Second argument must be a integer"))
+			return
+		}
+	}
+	file, err := os.Open(file_path)
+	if err != nil {
+		fmt.Println(fmt.Sprintf("Error opening file: %s", err.Error()))
+		return
+	}
+	defer file.Close()
+	size, err := CountLines(file)
+	file.Seek(0, io.SeekStart)
+	scanner := bufio.NewScanner(file)
+	if lines == 0 {
+		for i := 0; i < size; i++ {
+			if !scanner.Scan() {
+				return
+			}
+			if i >= (size - 10) {
+				fmt.Println(fmt.Sprintf(scanner.Text()))
+			}
+		}
+	} else {
+		for i := 0; i < size; i++ {
+			if !scanner.Scan() {
+				return
+			}
+			if i >= (size - lines) {
+				fmt.Println(fmt.Sprintf(scanner.Text()))
+			}
+		}
+	}
+}
+func CountLines(r io.Reader) (int, error) {
+	var count int
+	var read int
+	var err error
+	var target []byte = []byte("\n")
+
+	buffer := make([]byte, 32*1024)
+
+	for {
+		read, err = r.Read(buffer)
+		if err != nil {
+			break
+		}
+
+		count += bytes.Count(buffer[:read], target)
+	}
+
+	if err == io.EOF {
+		return count, nil
+	}
+
+	return count, err
+}

input_parser/input_parser.go

@@ -36,8 +36,14 @@ func parse(input string) Input {
 	var flags []string
 	var args []string
 	for _, arg := range split[1:] {
-		if len(arg) == 1 && arg[0] == '-' {
+		if len(arg) == 0 {
 			continue
+		} else if len(arg) == 1 {
+			if arg[0] == '-' {
+				continue
+			} else {
+				args = append(args, strings.TrimSpace(arg))
+			}
 		} else if arg[0:2] == "--" {
 			var result = strings.TrimSpace(arg)
 			flags = append(flags, string(result[2:]))
@@ -81,7 +87,7 @@ func input_str(env *environment.Env) string {
 	for {
 		r_rune, _, err := reader.ReadRune()
 		if err != nil {
-			fmt.Print(fmt.Sprintf("Error reading user input: %s", err.Error()))
+			fmt.Print(fmt.Sprintf("Error reading user input: ", err.Error()))
 		}
 		switch r_rune {
 		case 3: // ^C
@@ -90,32 +96,21 @@ func input_str(env *environment.Env) string {
 		case 4: // ^D
 			input = "exit"
 			goto loop_exit
-		case 27: // UPP
-			if r, _, _ := reader.ReadRune(); r != 91 {
-				break
+		case 65: // UPP
+			if history_index > 0 {
+				history_index--
+				input = env.History[history_index]
 			}
 		case 66: // DOWN
 			if history_index < len(env.History)-2 {
 				history_index++
 				input = env.History[history_index]
 			} else {
-				history_index = len(env.History)-1
+				history_index = len(env.History) - 1
 				input = ""
-				if r, _, _ := reader.ReadRune(); r == 65 { // UPP
-					if history_index > 0 {
-						history_index--
-						input = env.History[history_index]
-					}
-				}
-				if r, _, _ := reader.ReadRune(); r != 66 { //DOWN
-					if history_index < len(env.History)-1 {
-						history_index++
-						input = env.History[history_index]
-					} else {
-						input = ""
-					}
-				}
 			}
+		case 67: // LEFT
+		case 68: // RIGHT
 		case 127: //packspace
 			if len(input) > 0 {
 				input = input[:len(input)-1]