Implementation of ls and grep

C programs for the implementation of ls and grep for the operating systems lab. If you have any doubts, please let me know.

ls

#include<stdio.h>

#include<dirent.h>

main(int argc, char ** argv)

{

    DIR *dp;

    struct dirent *link;

    dp=opendir(argv[1]);

    printf("\n the contents of directory %s are \n",argv[1]);

     while((link==readdir(dp))!=0)

     printf("%s",link->d_name);

      closedir(dp);

}

GREP

#include<stdio.h>

#include<string.h>

#define max 1024

void usage()

{

   printf("usage:\t./a.out filename word\n");

}

int main(int argc, char *argv[])

{

   FILE *fp;

   char fline[max];

   int count=0;

   int occurrences=0;

   if(argc!=3)

   {

     usage();

      exit(1);

   }

   if(!(fp=fopen(argv[1],"r")))

   {

      printf("grep : could not open file: %s\n",argv[1]);

       exit(1);

   }

   while(fgets(fline,max,fp)!=NULL)

    {

        count++;

         if(newline=strchr(fline,'\n'))

         *newline='\0';

         if(strchr(fline,argv[2]!=NULL)

          {

              printf("%s: %d %s\n",argv[1],count,fline);

              occurrences++;

          }

      }

}