Lines of bin/cat/cat.c from check-in 60d6b3ed89 that are changed by the sequence of edits moving toward check-in 51201d4984:

60d6b3ed89 1980-10-01    1: static char *sccsid = "@(#)cat.c	4.1 (Berkeley) 10/01/80";
                         2: /*
                         3:  * Concatenate files.
                         4:  */
                         5: 
                         6: #include <stdio.h>
                         7: #include <sys/types.h>
                         8: #include <sys/stat.h>
                         9: 
                        10: char	stdbuf[BUFSIZ];
                        11: 
                        12: main(argc, argv)
                        13: char **argv;
                        14: {
                        15: 	int fflg = 0;
                        16: 	register FILE *fi;
                        17: 	register c;
                        18: 	int dev, ino = -1;
                        19: 	struct stat statb;
                        20: 
                        21: 	setbuf(stdout, stdbuf);
                        22: 	for( ; argc>1 && argv[1][0]=='-'; argc--,argv++) {
                        23: 		switch(argv[1][1]) {
                        24: 		case 0:
                        25: 			break;
                        26: 		case 'u':
                        27: 			setbuf(stdout, (char *)NULL);
                        28: 			continue;
                        29: 		}
                        30: 		break;
                        31: 	}
                        32: 	fstat(fileno(stdout), &statb);
                        33: 	statb.st_mode &= S_IFMT;
                        34: 	if (statb.st_mode!=S_IFCHR && statb.st_mode!=S_IFBLK) {
                        35: 		dev = statb.st_dev;
                        36: 		ino = statb.st_ino;
                        37: 	}
                        38: 	if (argc < 2) {
                        39: 		argc = 2;
                        40: 		fflg++;
                        41: 	}
                        42: 	while (--argc > 0) {
                        43: 		if (fflg || (*++argv)[0]=='-' && (*argv)[1]=='\0')
                        44: 			fi = stdin;
                        45: 		else {
                        46: 			if ((fi = fopen(*argv, "r")) == NULL) {
                        47: 				fprintf(stderr, "cat: can't open %s\n", *argv);
                        48: 				continue;
                        49: 			}
                        50: 		}
                        51: 		fstat(fileno(fi), &statb);
                        52: 		if (statb.st_dev==dev && statb.st_ino==ino) {
                        53: 			fprintf(stderr, "cat: input %s is output\n",
                        54: 			   fflg?"-": *argv);
                        55: 			fclose(fi);
                        56: 			continue;
                        57: 		}
60d6b3ed89 1980-10-01   58: 		while ((c = getc(fi)) != EOF)
60d6b3ed89 1980-10-01   59: 			putchar(c);
                        60: 		if (fi!=stdin)
                        61: 			fclose(fi);
                        62: 	}
                        63: 	return(0);
                        64: }