CS456 - Systems Programming Spring 2025

Displaying ./code/h1/copy.c

/*

implementing a version of the "cp" command

*/
#include <stdio.h>
#include <stdlib.h>

int main(int argc, char **argv){

	if(argc < 3){   //prints usage statement if not enough arguments
		fprintf(stderr,"Usage: %s <src> <dst>\n", argv[0]);
		exit(1);
	}

	//declares file pointer, tries to open file specified by user
	FILE *src, *dst; 
	src = fopen(argv[1], "r"); //source file
	dst = fopen(argv[2], "w"); //destination

	//if file does not exist, print usage statement and exit the program
	if(src == NULL){
		fprintf(stderr, "ERROR: Cannot open %s, file probably does not exist.\n", argv[1]);
		exit(-1);:
	}

	// if we get here, we then read every character in the source file, 
	// and then write the character to the destination file
	char c;
	while((c=fgetc(src))){

		if(c == EOF) break; //we've reached the end of file, break the loop

		fputc(c, dst); //writing the character to the destination file.

	}

	fclose(src); //close the source file
	fclose(dst); //close the destination file

	return 0;

}