2 * Copyright (c) 1991, 1993
3 * The Regents of the University of California. All rights reserved.
5 * This code is derived from software contributed to Berkeley by
6 * Edward Sze-Tyan Wang.
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions
11 * 1. Redistributions of source code must retain the above copyright
12 * notice, this list of conditions and the following disclaimer.
13 * 2. Redistributions in binary form must reproduce the above copyright
14 * notice, this list of conditions and the following disclaimer in the
15 * documentation and/or other materials provided with the distribution.
16 * 3. All advertising materials mentioning features or use of this software
17 * must display the following acknowledgement:
18 * This product includes software developed by the University of
19 * California, Berkeley and its contributors.
20 * 4. Neither the name of the University nor the names of its contributors
21 * may be used to endorse or promote products derived from this software
22 * without specific prior written permission.
24 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
25 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
26 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
27 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
28 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
29 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
30 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
31 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
32 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
33 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
38 static char copyright[] =
39 "@(#) Copyright (c) 1991, 1993\n\
40 The Regents of the University of California. All rights reserved.\n";
44 static char sccsid[] = "@(#)tail.c 8.1 (Berkeley) 6/6/93";
47 #include <sys/types.h>
57 int Fflag, fflag, rflag, rval;
60 static void obsolete __P((char **));
61 static void usage __P((void));
76 * Tail's options are weird. First, -n10 is the same as -n-10, not
77 * -n+10. Second, the number options are 1 based and not offsets,
78 * so -n+1 is the first line, and -c-1 is the last byte. Third, the
79 * number options for the -r option specify the number of things that
80 * get displayed, not the starting point in the file. The one major
81 * incompatibility in this version as compared to historical versions
82 * is that the 'r' option couldn't be modified by the -lbc options,
83 * i.e. it was always done in lines. This version treats -rc as a
84 * number of characters in reverse order. Finally, the default for
85 * -r is the entire file, not 10 lines.
87 #define ARG(units, forward, backward) { \
90 off = strtol(optarg, &p, 10) * (units); \
92 errx(1, "illegal offset -- %s", optarg); \
103 style = (backward); \
110 while ((ch = getopt(argc, argv, "Fb:c:fn:r")) != -1)
112 case 'F': /* -F is superset of (and implies) -f */
116 ARG(512, FBYTES, RBYTES);
119 ARG(1, FBYTES, RBYTES);
125 ARG(1, FLINES, RLINES);
137 if (fflag && argc > 1)
138 errx(1, "-f option only appropriate for a single file");
141 * If displaying in reverse, don't permit follow option, and convert
149 else if (style == FLINES)
154 * If style not specified, the default is the whole file for -r, and
155 * the last 10 lines if not -r.
157 if (style == NOTSET) {
168 for (first = 1; fname = *argv++;) {
169 if ((fp = fopen(fname, "r")) == NULL ||
170 fstat(fileno(fp), &sb)) {
175 (void)printf("%s==> %s <==\n",
176 first ? "" : "\n", fname);
178 (void)fflush(stdout);
182 reverse(fp, style, off, &sb);
184 forward(fp, style, off, &sb);
190 if (fstat(fileno(stdin), &sb)) {
196 * Determine if input is a pipe. 4.4BSD will set the SOCKET
197 * bit in the st_mode field for pipes. Fix this then.
199 if (lseek(fileno(stdin), (off_t)0, SEEK_CUR) == -1 &&
202 fflag = 0; /* POSIX.2 requires this. */
206 reverse(stdin, style, off, &sb);
208 forward(stdin, style, off, &sb);
214 * Convert the obsolete argument form into something that getopt can handle.
215 * This means that anything of the form [+-][0-9][0-9]*[lbc][fr] that isn't
216 * the option argument for a -b, -c or -n option gets converted.
222 register char *ap, *p, *t;
226 while (ap = *++argv) {
227 /* Return if "--" or not an option of any form. */
231 } else if (ap[1] == '-')
235 /* Old-style option. */
236 case '0': case '1': case '2': case '3': case '4':
237 case '5': case '6': case '7': case '8': case '9':
239 /* Malloc space for dash, new option and argument. */
241 if ((start = p = malloc(len + 3)) == NULL)
246 * Go to the end of the option argument. Save off any
247 * trailing options (-3lf) and translate any trailing
248 * output style characters.
251 if (*t == 'f' || *t == 'r') {
267 case '0': case '1': case '2': case '3': case '4':
268 case '5': case '6': case '7': case '8': case '9':
272 errx(1, "illegal option -- %s", *argv);
280 * Options w/ arguments, skip the argument and continue
281 * with the next option.
289 /* Options w/o arguments, continue with the next option. */
294 /* Illegal option, return and let getopt handle it. */
304 (void)fprintf(stderr,
305 "usage: tail [-f | -r] [-b # | -c # | -n #] [file ...]\n");