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. Neither the name of the University nor the names of its contributors
17 * may be used to endorse or promote products derived from this software
18 * without specific prior written permission.
20 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
21 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
22 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
23 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
24 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
25 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
26 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
27 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
28 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
29 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
33 #include <sys/cdefs.h>
35 __FBSDID("$FreeBSD$");
38 static const char copyright[] =
39 "@(#) Copyright (c) 1991, 1993\n\
40 The Regents of the University of California. All rights reserved.\n";
44 static const char sccsid[] = "@(#)tail.c 8.1 (Berkeley) 6/6/93";
47 #include <sys/types.h>
59 int Fflag, fflag, qflag, rflag, rval, no_files;
61 static file_info_t *files;
63 static void obsolete(char **);
64 static void usage(void);
67 main(int argc, char *argv[])
79 * Tail's options are weird. First, -n10 is the same as -n-10, not
80 * -n+10. Second, the number options are 1 based and not offsets,
81 * so -n+1 is the first line, and -c-1 is the last byte. Third, the
82 * number options for the -r option specify the number of things that
83 * get displayed, not the starting point in the file. The one major
84 * incompatibility in this version as compared to historical versions
85 * is that the 'r' option couldn't be modified by the -lbc options,
86 * i.e. it was always done in lines. This version treats -rc as a
87 * number of characters in reverse order. Finally, the default for
88 * -r is the entire file, not 10 lines.
90 #define ARG(units, forward, backward) { \
93 off = strtoll(optarg, &p, 10) * (units); \
95 errx(1, "illegal offset -- %s", optarg); \
106 style = (backward); \
114 while ((ch = getopt(argc, argv, "Fb:c:fn:qr")) != -1)
116 case 'F': /* -F is superset of (and implies) -f */
120 ARG(512, FBYTES, RBYTES);
123 ARG(1, FBYTES, RBYTES);
129 ARG(1, FLINES, RLINES);
144 no_files = argc ? argc : 1;
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) {
173 if (*argv && fflag) {
174 files = (struct file_info *) malloc(no_files *
175 sizeof(struct file_info));
177 err(1, "Couldn't malloc space for file descriptors.");
179 for (file = files; (fn = *argv++); file++) {
180 file->file_name = strdup(fn);
181 if (! file->file_name)
182 errx(1, "Couldn't malloc space for file name.");
183 if ((file->fp = fopen(file->file_name, "r")) == NULL ||
184 fstat(fileno(file->fp), &file->st)) {
185 if (file->fp != NULL) {
189 if (!Fflag || errno != ENOENT)
190 ierr(file->file_name);
193 follow(files, style, off);
194 for (i = 0, file = files; i < no_files; i++, file++) {
195 free(file->file_name);
199 for (first = 1; (fn = *argv++);) {
200 if ((fp = fopen(fn, "r")) == NULL ||
201 fstat(fileno(fp), &sb)) {
205 if (argc > 1 && !qflag) {
211 reverse(fp, fn, style, off, &sb);
213 forward(fp, fn, style, off, &sb);
218 if (fstat(fileno(stdin), &sb)) {
224 * Determine if input is a pipe. 4.4BSD will set the SOCKET
225 * bit in the st_mode field for pipes. Fix this then.
227 if (lseek(fileno(stdin), (off_t)0, SEEK_CUR) == -1 &&
230 fflag = 0; /* POSIX.2 requires this. */
234 reverse(stdin, fn, style, off, &sb);
236 forward(stdin, fn, style, off, &sb);
242 * Convert the obsolete argument form into something that getopt can handle.
243 * This means that anything of the form [+-][0-9][0-9]*[lbc][Ffr] that isn't
244 * the option argument for a -b, -c or -n option gets converted.
247 obsolete(char *argv[])
253 while ((ap = *++argv)) {
254 /* Return if "--" or not an option of any form. */
258 } else if (ap[1] == '-')
262 /* Old-style option. */
263 case '0': case '1': case '2': case '3': case '4':
264 case '5': case '6': case '7': case '8': case '9':
266 /* Malloc space for dash, new option and argument. */
268 if ((start = p = malloc(len + 3)) == NULL)
273 * Go to the end of the option argument. Save off any
274 * trailing options (-3lf) and translate any trailing
275 * output style characters.
278 if (*t == 'F' || *t == 'f' || *t == 'r') {
294 case '0': case '1': case '2': case '3': case '4':
295 case '5': case '6': case '7': case '8': case '9':
299 errx(1, "illegal option -- %s", *argv);
307 * Options w/ arguments, skip the argument and continue
308 * with the next option.
316 /* Options w/o arguments, continue with the next option. */
322 /* Illegal option, return and let getopt handle it. */
332 (void)fprintf(stderr,
333 "usage: tail [-F | -f | -r] [-q] [-b # | -c # | -n #]"