demo1.c

#include<stdio.h>
#include<unistd.h>
#include<stdlib.h>
#include<sys/types.h>
#include<sys/wait.h>
#include <string.h> 
#include <ctype.h>
#include "ls.c"
#include "mkdir.c"
#include "cat.c"
#include "rm.c"
#include "date.c"
void pwd();
void cd(char parsed[1000][1000]);
int parser(char input[1000],char parsed[1000][1000]);
void echo(char input[1000]);
void history(char parsed[1000][1000]);

FILE *fptr;


int main() {
    while(1){
		char cwd[256] = {};
		getcwd(cwd, 256);
		printf("%s%s%s", "myterminal@arka:~",cwd," $ ");
		char input[1000] = {};
		char parsed[1000][1000] = {{}};
		FILE *ptr;
		ptr = fopen("/home/arkasarkar/Desktop/CAOS/history.txt","a");
		fgets(input,1000,stdin);
		int com = parser(input,parsed);
		fputs(input,ptr);
		fclose(ptr);
		int i;
		switch (com)
		{
		case 0:
			printf("%s\n", "command not found ");
		case 1:
			 cd(parsed);				
			break;
		case 2:
			cat(parsed);
			break;
		case 3:
			echo(input);
			break;
		case 4:
			i = 8;
			int flag = 0;
			while(input[i]!='\0' && input[i]!='\n'){
				if(input[i]=='c'){
					flag = 1;
					break;
				}
				else if(input[i]=='d'){
					flag = 2;
					break;
				}
				else;
				++i;
			}
			if(flag==0) history(parsed);
			else if(flag==1) {
				remove("/home/arkasarkar/Desktop/CAOS/history.txt");
				fopen("/home/arkasarkar/Desktop/CAOS/history.txt","w");
			}
			break;
		case 5:
			pwd();
			break;
		case 6:
			exit(0);
			break;
		case 7:
			rm(parsed);
			break;
		case 8:
			ls1(input);
			break;
		case 9:
			mkdir(parsed);
			break;
		case 10:
			date(parsed);
			break;
		default:
			printf("%s\n", "command not found ");
			break;
		}
	 }
}
void history(char parsed[1000][1000]){
	int i=0;
	int flag = 0;
	char n ;
	while(i<1000 && *parsed[i]!='\n'){
		if(flag==0 && strcmp(parsed[i],"history")==0){
			flag = 1;
		}
		// else if(flag==1 && isdigit(parsed[i])){
		// 	n = *parsed[i];
		// 	flag = 2;
		// }
		++i;
	}
	if(flag == 1){
	fptr = fopen("/home/arkasarkar/Desktop/CAOS/history.txt","r");
	char h = fgetc(fptr);
    while (h != EOF)
    {   printf ("%c", h);
        h = fgetc(fptr);
	}
    fclose(fptr);
	}
	if(flag == 2){
		fptr = fopen("/home/arkasarkar/Desktop/CAOS/history.txt","r");
	char h = fgetc(fptr);
    while (n-->0)
    {   printf ("%c", h);
        h = fgetc(fptr);
	}
    fclose(fptr);
	}
	}

void echo(char input[1000]){
	int i=0;
	while(input[i]!='\0' || input[i]!='\n'){
		if(input[i]=='e' && input[i+1]=='c'&& input[i+2] == 'h'&& input[i+3] == 'o') break;
		++i;
	}

	int j = i+5;
	int flag = 0;

	while(j<1000 && (input[j]!='\0' && input[j]!='\n')){
		if(flag==0 && input[j] == '"') break;
		else if(flag == 0 && input[j] == '-'){
			flag = 1;
			
		}
		else if(flag == 0 && input[j] == '*'){
			flag = 4;
			
		}	

		else if(flag==1 && input[j]=='n'){
			flag = 2;
			break;
		}
		else if(flag==1 && input[j]=='e'){
			flag = 3;
			break;
		}
		else;
		++j;
	}
	char string[256] = {};
	int o = 0;
	if(flag == 0){
		while(j<1000 && o<256 &&  (input[j]!='\0'&& input[j]!='\n')){
			if(input[j]!='"' && input[j]!='\n'){
			string[o] = input[j];
			++o;
		}
		++j;
	}
	printf("%s\n", string);
	}

	if(flag==2){
			int first = 0;

		j = j+1;
		while(j<1000 && o<256 &&  (input[j]!='\0' || input[j]!='\n')){
			if(input[j]=='"') first = 1;
			if(first ==1 && input[j]!='"' && input[j]!='\n'){
			string[o] = input[j];
			++o;
		}
		++j;
	}
	printf("%s", string);
	}
	if(flag==4){
		pid_t pid;
	pid = fork();
	if(pid<0){
		printf("%s\n", "Some error occurred");
	}
	else if(pid==0){
		execl("/bin/ls","ls",(char *)0);
	}
	else{
		wait(NULL);
	}
	}


}
void pwd(){
	char cwd[256];
   if (*getcwd(cwd, 256) != '\0') {
       printf("%s%s\n", "current working directory :- " ,cwd);
   }
   else{
	   printf("Error in pwd");
   }
}

void cd(char parsed[1000][1000]){
	int i=0;
	while(i<1000 && *parsed[i]!='\n'){
		if(strcmp(parsed[i],"cd")!=0){
			break;
		}
		++i;
	}
	if(parsed[i][0]=='\0' || parsed[i][0] =='~') chdir("/home/arkasarkar");
	else chdir(parsed[i])	;
	
}
int parser(char input[1000],char parsed[1000][1000]){
	int i=0;
    int j=0;
    int o = 0;
	for(i=0;i<1000;i++){
		 if(input[i]==' ' || input[i]=='\n' ){
            ++j;
            o = 0;
        }
        else{
            parsed[j][o] = input[i];
            ++o;
        }
	}
	i = 0;
	j = 0;
	if(*parsed[0]=='\n') return 0;
	while(i<1000 && *parsed[i]!='\n'){
		if(strcmp(parsed[i],"cd")==0){
			j=1;
			break;
		}
		if(strcmp(parsed[i],"cat")==0){
			j=2;
			break;
		}
		if(strcmp(parsed[i],"echo")==0){
			j=3;
			break;
		}
		if(strcmp(parsed[i],"history")==0){
			j=4;
			break;
		}
		if(strcmp(parsed[i],"pwd")==0){
			j=5;
			break;
		}
		if(strcmp(parsed[i],"exit")==0){
			j=6;
			break;
		}
		if(strcmp(parsed[i],"rm")==0){
			j=7;
			break;
		}
		if(strcmp(parsed[i],"ls")==0){
			j=8;
			break;
		}
		if(strcmp(parsed[i],"mkdir")==0){
			j=9;
			break;
		}
		
		if(strcmp(parsed[i],"date")==0){
			j=10;
			break;
		}

		
		++i;
	}
	return j;

}