search

#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <sys/wait.h>
#include <string.h>
#include <fcntl.h>

int numberOfTokens = 0;
char cmd[100];
char tokenOne[20];
char tokenTwo[20];
char tokenThree[20];
char tokenFour[20];

int main(void)
{
void search(char *,char *,char *);

while(1)
{
	printf("MyShell$] ");

	fgets(cmd,sizeof(cmd),stdin);

	numberOfTokens = sscanf(cmd,"%s %s %s %s",tokenOne,tokenTwo,tokenThree,tokenFour);

	switch(numberOfTokens)
	{
		case 1:
			if(strcmp(tokenOne,"exit") == 0)
			{
				exit(0);
			}
			if(fork() == 0)
			{
				execlp(tokenOne,tokenOne,NULL);
			}
			wait(0);
			break;
			
		case 2:
			if(fork() == 0)
			{
				execlp(tokenOne,tokenOne,tokenTwo,NULL);
			}
			wait(0);
			break;

		case 3:
			if(fork() == 0)
			{
				execlp(tokenOne,tokenOne,tokenTwo,tokenThree,NULL);
			}
			wait(0);
			break;

		case 4:
			if(strcmp(tokenOne,"search") == 0)
			{
				search(tokenTwo,tokenThree,tokenFour);
			}
			else if(fork() == 0)
			{
				execlp(tokenOne,tokenOne,tokenTwo,tokenThree,NULL);
			}
			wait(0);
			break;
	}
}

return(0);

}

void search(char *option, char *pattern,char *fname)
{
int handle;
int i = 0;
int count = 0;

handle = open(fname,O_RDONLY);

char data[200] = {'\0'};
char ch;
char *ptr = NULL;

if(handle == -1)
{
	printf("\nError While Opening %s File !!!\n",fname);
	exit(-1);
}

if((strcmp(option,"f") == 0) || (strcmp(option,"F") == 0))
{
	i = 0;
	while(read(handle,&ch,1))
	{
		data[i] = ch;
		i++;

		if(ch == '\n')
		{
			data[i] = '\0';
			if(strstr(data,pattern) != NULL)
			{
				printf("First Occurance Of \" %s \" In Line :\n%s",pattern,data);
				close(handle);
				break;
			}

			i = 0;
		}
	}
}
else if((strcmp(option,"A") == 0) || (strcmp(option,"a") == 0))
{
	i = 0;
	while(read(handle,&ch,1))
	{
		data[i] = ch;
		i++;

		if(ch == '\n')
		{
			data[i] = '\0';
			if(strstr(data,pattern) != NULL)
			{
				printf("%s",data);
			}
			i = 0;
		}
	}
}
else if((strcmp(option,"C") == 0) || strcmp(option,"c") == 0)
{
	i = 0;
	count = 0;
	while(read(handle,&ch,1))
	{
		data[i] = ch;
		i++;
		if(ch == '\n')
		{
			data[i] = '\0';

			ptr = data;

			while((ptr = strstr(ptr,pattern)) != NULL) 
			{
				ptr++;
				count++;
			}

			i = 0;
		}
	}

	printf("\n%s Found %d Times\n",pattern,count);
}

close(handle);

}