sign denotes the path of that header file. “header.h” includes the path of current directory in which various directories are placed.

NULL 1 IT is macrodefined in for the null pointer . 2 NULL CAN BE DEFINED AS ((void*)0) 3 size of NULL= 4BYTES NUL 1 IT IS A USER DEFINED VARIABLE. 2 IST CHAR IN THE ASCII TABLE. 3 IT … Continue reading →

we can exit from superuser by using exit command . exit changing the password of root passwd

//header.h// #include 2 #include 3 #define MAX 5 4 int push(void **,int *); 5 int pop(void **,int *); 6 void display(void **,int *); //fun.c// #include”abc.h” 2 int push(void **astack,int *atop) 3 { 4 static char ch=1; 5 if(*atop >= MAX-1) … Continue reading →

@#include 32 #include 33 #include 34 #include 35 int main() 36 { 37 char arr[55],m[55],ch1,ch2; 38 int fd,j,ret,i=0,len; 39 fd =open(“text”,O_RDONLY); 40 read(fd,&arr,55); 41 len=strlen(arr); 42 printf(“lenght of string is %d\n”,len); 43 if(fd<0) 44 { 45 perror("read"); 46 exit(-1); 47 … Continue reading →

check if package is already present or not by using rpm -q vsftpd    (as the rpm package for ftp is vsftpd) if not present then yum install vsftpd yum y install after that service vsftpd start