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
37 #include <sys/cdefs.h>
39 __FBSDID("$FreeBSD$");
42 static const char copyright[] =
43 "@(#) Copyright (c) 1991, 1993\n\
44 The Regents of the University of California. All rights reserved.\n";
48 static const char sccsid[] = "@(#)tail.c 8.1 (Berkeley) 6/6/93";
51 #include <sys/types.h>
63 int Fflag, fflag, rflag, rval;
66 static void obsolete(char **);
67 static void usage(void);
82 * Tail's options are weird. First, -n10 is the same as -n-10, not
83 * -n+10. Second, the number options are 1 based and not offsets,
84 * so -n+1 is the first line, and -c-1 is the last byte. Third, the
85 * number options for the -r option specify the number of things that
86 * get displayed, not the starting point in the file. The one major
87 * incompatibility in this version as compared to historical versions
88 * is that the 'r' option couldn't be modified by the -lbc options,
89 * i.e. it was always done in lines. This version treats -rc as a
90 * number of characters in reverse order. Finally, the default for
91 * -r is the entire file, not 10 lines.
93 #define ARG(units, forward, backward) { \
96 off = strtoll(optarg, &p, 10) * (units); \
98 errx(1, "illegal offset -- %s", optarg); \
109 style = (backward); \
116 while ((ch = getopt(argc, argv, "Fb:c:fn:r")) != -1)
118 case 'F': /* -F is superset of (and implies) -f */
122 ARG(512, FBYTES, RBYTES);
125 ARG(1, FBYTES, RBYTES);
131 ARG(1, FLINES, RLINES);
143 if (fflag && argc > 1)
144 errx(1, "-f option only appropriate for a single file");
147 * If displaying in reverse, don't permit follow option, and convert
155 else if (style == FLINES)
160 * If style not specified, the default is the whole file for -r, and
161 * the last 10 lines if not -r.
163 if (style == NOTSET) {
174 for (first = 1; (fname = *argv++);) {
175 if ((fp = fopen(fname, "r")) == NULL ||
176 fstat(fileno(fp), &sb)) {
181 (void)printf("%s==> %s <==\n",
182 first ? "" : "\n", fname);
184 (void)fflush(stdout);
188 reverse(fp, style, off, &sb);
190 forward(fp, style, off, &sb);
196 if (fstat(fileno(stdin), &sb)) {
202 * Determine if input is a pipe. 4.4BSD will set the SOCKET
203 * bit in the st_mode field for pipes. Fix this then.
205 if (lseek(fileno(stdin), (off_t)0, SEEK_CUR) == -1 &&
208 fflag = 0; /* POSIX.2 requires this. */
212 reverse(stdin, style, off, &sb);
214 forward(stdin, style, off, &sb);
220 * Convert the obsolete argument form into something that getopt can handle.
221 * This means that anything of the form [+-][0-9][0-9]*[lbc][Ffr] that isn't
222 * the option argument for a -b, -c or -n option gets converted.
232 while ((ap = *++argv)) {
233 /* Return if "--" or not an option of any form. */
237 } else if (ap[1] == '-')
241 /* Old-style option. */
242 case '0': case '1': case '2': case '3': case '4':
243 case '5': case '6': case '7': case '8': case '9':
245 /* Malloc space for dash, new option and argument. */
247 if ((start = p = malloc(len + 3)) == NULL)
252 * Go to the end of the option argument. Save off any
253 * trailing options (-3lf) and translate any trailing
254 * output style characters.
257 if (*t == 'F' || *t == 'f' || *t == 'r') {
273 case '0': case '1': case '2': case '3': case '4':
274 case '5': case '6': case '7': case '8': case '9':
278 errx(1, "illegal option -- %s", *argv);
286 * Options w/ arguments, skip the argument and continue
287 * with the next option.
295 /* Options w/o arguments, continue with the next option. */
301 /* Illegal option, return and let getopt handle it. */
311 (void)fprintf(stderr,
312 "usage: tail [-F | -f | -r] [-b # | -c # | -n #] [file ...]\n");