Question

Write a C program to Simulate Implementation of Linux *cp* command.

Copying Files and directories

Answer 1

Please find my implemetation:

Here is the code for you:

#include <stdio.h>
#include <unistd.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <string.h>
int main(int argc, char *argv[])
{
char fileName[50];
if(argc != 3)
{
printf("Error. Usage: mycp source_file target_file\n");
return 0;
}
strcpy(fileName, argv[1]);
//Attempts to open the file with the name specified by the user (using the open system call) in read only mode.
int fdIn = open((const char *)fileName, O_RDONLY);
//Displays an error message and quits the program if file open is unsuccessful.
if(fdIn == -1)
{
printf("Error: Source file doesn't exist.\n");
return 0;
}
strcpy(fileName, argv[2]);
int fdOut = open((const char *)fileName, O_RDONLY);
if(fdOut != -1)
{
printf("Error: Destination file readily exist.\n");
return 0;
}
close(fdOut);
fdOut = open((const char *)fileName, O_CREAT);
fdOut = open((const char *)fileName, O_WRONLY);
char buffer;
int byteCount = 0;
while(read(fdIn, &buffer, 1))
{
write(fdOut, &buffer, 1);
byteCount++;
}   
close(fdIn);
close(fdOut);
printf("Copied %d bytes\n", byteCount);
}