Simulation of Unix Commands - wc

SIMULATION OF UNIX COMMANDS - Word Count (wc)

Programs

// 4. wc command

#include<stdio.h>

int wc,lc,cc;

main(int argc, char * argv[] )

{

FILE *fp;

int i;

char a[100];

if(argc!=2)

{

          printf(“Usage error”);

          return;

}

fp = fopen(argv[1],"r");

if(fp==NULL)

{

          printf("File opening error");

          return;

}

i=load(fp,a);

while(i==1)

{

          count(a);

          i=load(fp,a);

}

printf("\nWord Count : %d", wc);

printf("\nLine Count : %d", lc);

printf("\nCharacter Count : %d", cc);

close(fp);

}

load(fp1,g)

FILE *fp1;

char g[];

{

          int n;

         

          for(n=0;(g[n]=getc(fp1))!=EOF;n++)

                   if(g[n]=='\n')

                   {

                             g[n]='\0';

                             return 1;

                   }

          return 0;

}

count(g)

char g[];

{

          int n;

          for(n=0;g[n]!='\0';n++)

          {

                   lc++;

                   if(g[n]!='\t' && g[n]!=' ' )

                             cc++;

                   if( (g[n]=='\t' && g[n+1]!='\t' )||(g[n]==' ' && g[n+1]!=' ' ) )

                             wc++;

          }

}

Simulation of Unix Commands - cat

SIMULATION OF UNIX COMMANDS

Programs

// 2. cat command

#include<fcntl.h>                                     

#include<sys/stat.h>

#define BUFSIZE 1

int main(int argc, char **argv)

{

          int fd1;

          int n;

          char buf;

          fd1=open(argv[1],O_RDONLY);

  

while((n=read(fd1,&buf,1))>0)   

printf("%c",buf);

return (0);

}

Simulation of Unix Commands - ls

SIMULATION OF UNIX COMMANDS

Programs

// 1. ls command

#include<stdio.h>                                     

#include<fcntl.h>

#include<sys/stat.h>                       

#include<dirent.h>

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

{

DIR *dp;

struct dirent *sd;

dp=opendir(argv[1]);

while((sd=readdir(dp))!=NULL)

printf("%s\t",sd->d_name);

closedir(dp);

}

Simulation of Unix Commands - grep

SIMULATION OF UNIX COMMANDS

Programs

// 3. Grep command

#include <stdio.h>                 

#include <stdlib.h>

int substr( char *line, char *pat);

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

{

        FILE *fp;

        char line[128];

        if ( argc == 2 )

                fp = stdin;

        else if ( argc == 3 )

        {

                fp = fopen(argv[2], "r");

                if ( fp == NULL )

                        printf("file %s cannot be opened \n", argv[1]);

        }

        else

        {

                printf("Usage: %s <pattern> <file> \n", argv[0]);

                exit(1);

        }

        while( fgets(line, sizeof(line), fp) )

                if ( substr(line, argv[1]) )

                        printf("%s",line);

        fclose (fp);

        return 0;

}

int substr( char *line, char *pat)

{

        int i,j,k;

        for( i=0; line[i] != '\0'; i++)

                for( j=i,k=0; line[j]==pat[k] && pat[k] != '\0'; j++,k++);

                             if ( pat[k] == '\0')

                                      return 1;

        return 0;

}