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, no_files;
68 static void obsolete(char **);
69 static void usage(void);
72 main(int argc, char *argv[])
83 * Tail's options are weird. First, -n10 is the same as -n-10, not
84 * -n+10. Second, the number options are 1 based and not offsets,
85 * so -n+1 is the first line, and -c-1 is the last byte. Third, the
86 * number options for the -r option specify the number of things that
87 * get displayed, not the starting point in the file. The one major
88 * incompatibility in this version as compared to historical versions
89 * is that the 'r' option couldn't be modified by the -lbc options,
90 * i.e. it was always done in lines. This version treats -rc as a
91 * number of characters in reverse order. Finally, the default for
92 * -r is the entire file, not 10 lines.
94 #define ARG(units, forward, backward) { \
97 off = strtoll(optarg, &p, 10) * (units); \
99 errx(1, "illegal offset -- %s", optarg); \
100 switch(optarg[0]) { \
110 style = (backward); \
117 while ((ch = getopt(argc, argv, "Fb:c:fn:r")) != -1)
119 case 'F': /* -F is superset of (and implies) -f */
123 ARG(512, FBYTES, RBYTES);
126 ARG(1, FBYTES, RBYTES);
132 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 * sizeof(struct file_info));
176 err(1, "Couldn't malloc space for file descriptors.");
178 for (file = files; (fname = *argv++); file++) {
179 file->file_name = malloc(strlen(fname)+1);
180 if (! file->file_name)
181 errx(1, "Couldn't malloc space for file name.");
182 strncpy(file->file_name, fname, strlen(fname)+1);
183 if ((file->fp = fopen(file->file_name, "r")) == NULL ||
184 fstat(fileno(file->fp), &file->st)) {
190 follow(files, style, off);
191 for (i = 0, file = files; i < no_files; i++, file++) {
192 free(file->file_name);
196 for (first = 1; (fname = *argv++);) {
197 if ((fp = fopen(fname, "r")) == NULL ||
198 fstat(fileno(fp), &sb)) {
203 (void)printf("%s==> %s <==\n",
204 first ? "" : "\n", fname);
206 (void)fflush(stdout);
210 reverse(fp, style, off, &sb);
212 forward(fp, style, off, &sb);
217 if (fstat(fileno(stdin), &sb)) {
223 * Determine if input is a pipe. 4.4BSD will set the SOCKET
224 * bit in the st_mode field for pipes. Fix this then.
226 if (lseek(fileno(stdin), (off_t)0, SEEK_CUR) == -1 &&
229 fflag = 0; /* POSIX.2 requires this. */
233 reverse(stdin, style, off, &sb);
235 forward(stdin, style, off, &sb);
241 * Convert the obsolete argument form into something that getopt can handle.
242 * This means that anything of the form [+-][0-9][0-9]*[lbc][Ffr] that isn't
243 * the option argument for a -b, -c or -n option gets converted.
246 obsolete(char *argv[])
252 while ((ap = *++argv)) {
253 /* Return if "--" or not an option of any form. */
257 } else if (ap[1] == '-')
261 /* Old-style option. */
262 case '0': case '1': case '2': case '3': case '4':
263 case '5': case '6': case '7': case '8': case '9':
265 /* Malloc space for dash, new option and argument. */
267 if ((start = p = malloc(len + 3)) == NULL)
272 * Go to the end of the option argument. Save off any
273 * trailing options (-3lf) and translate any trailing
274 * output style characters.
277 if (*t == 'F' || *t == 'f' || *t == 'r') {
293 case '0': case '1': case '2': case '3': case '4':
294 case '5': case '6': case '7': case '8': case '9':
298 errx(1, "illegal option -- %s", *argv);
306 * Options w/ arguments, skip the argument and continue
307 * with the next option.
315 /* Options w/o arguments, continue with the next option. */
321 /* Illegal option, return and let getopt handle it. */
331 (void)fprintf(stderr,
332 "usage: tail [-F | -f | -r] [-b # | -c # | -n #] [file ...]\n");