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// cat - concatenate and print files
// https://pubs.opengroup.org/onlinepubs/9699919799/
//
// TODO: Add -u flag "Write bytes from the input file to the standard
// output without delay as each is read."
#include "include.h"
#include <dirent.h>
#include <fcntl.h>
#include <stdio.h>
#include <string.h>
#include <unistd.h>
int fd_to_stdout(int fd) {
int rc;
for (char buffer[CAT_BUFFER]; (rc = read(fd, &buffer, sizeof(buffer)));) {
if (-1 == rc)
return 0;
if (-1 == write(fd_stdout, buffer, rc))
return 0;
}
return 1;
}
int cat_main(int argc, char **argv) {
int fd = STDIN_FILENO;
// If no file operands are specified, the standard input shall be
// used.
if (argc < 2) {
return (fd_to_stdout(0)) ? 0 : 1;
}
argv++;
for (; *argv; argv++) {
// If a file is '-', the cat utility shall read from the standard
// input at that point in the sequence.
if (0 == strcmp(*argv, "-")) {
if (!fd_to_stdout(0))
return 1;
continue;
}
if (-1 == (fd = open(*argv, O_RDONLY, 0))) {
printf("cat: ");
// fflush(stdout);
perror(*argv);
return 1;
}
if (!fd_to_stdout(fd))
return 1;
close(fd);
}
return 0;
}
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