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/* Change <sys/file.h> to <sys/fcntl.h> if you're on System V.
*/
#include <sys/file.h>
main(argc, argv)
int argc;
char **argv;
{
int n;
int from, to;
char buf[1024];
/*
* Check our arguments. Note that to write the error
* message we can't just use "%s" as we did in Example
* 2-3; we have to write each string separately.
*/
if (argc != 3) {
write(2, "Usage: ", 7);
write(2, *argv, strlen(*argv));
write(2, " from-file to-file\n", 19);
exit(1);
}
/*
* Open the from-file for reading.
*/
if ((from = open(argv[1], O_RDONLY)) < 0) {
perror(argv[1]);
exit(1);
}
/*
* Open the to-file for appending. If to-file does
* not exist, open will create it with mode 644
* (-rw-r--r--). Note that we specify the mode
* in octal, not decimal
*/
if ((to = open(argv[2], O_WRONLY|O_CREAT|O_APPEND, 0644)) < 0) {
perror(argv[2]);
exit(1);
}
/*
* Now read a buffer-full at a time from the from-file,
* and write it to the to-file. Note that we only
* write the number of characters read read in,
* rather than always writing 1024 characters.
*/
while ((n = read(from, buf, sizeof(buf))) > 0)
write(to, buf, n);
/*
* Now close the files.
*/
close(from);
close(to);
exit(0);
}
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