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
32 * @(#) Copyright (c) 1991, 1993 The Regents of the University of California. All rights reserved.
33 * @(#)tail.c 8.1 (Berkeley) 6/6/93
34 * $FreeBSD: src/usr.bin/tail/tail.c,v 1.6.2.2 2001/12/19 20:29:31 iedowse Exp $
35 * $DragonFly: src/usr.bin/tail/tail.c,v 1.6 2005/03/01 21:37:33 cpressey Exp $
38 #include <sys/types.h>
48 int Fflag, fflag, rflag, rval, no_files;
53 static void obsolete(char **);
54 static void usage(void);
55 static void getarg(int, enum STYLE, enum STYLE, enum STYLE *, int *, off_t *);
58 main(int argc, char **argv)
70 while ((ch = getopt(argc, argv, "Fb:c:fn:r")) != -1)
72 case 'F': /* -F is superset of (and implies) -f */
76 getarg(512, FBYTES, RBYTES, &style, &style_set, &off);
79 getarg(1, FBYTES, RBYTES, &style, &style_set, &off);
85 getarg(1, FLINES, RLINES, &style, &style_set, &off);
97 no_files = argc ? argc : 1;
100 * If displaying in reverse, don't permit follow option, and convert
108 else if (style == FLINES)
113 * If style not specified, the default is the whole file for -r, and
114 * the last 10 lines if not -r.
126 if (*argv && fflag) {
127 files = malloc(no_files * sizeof(struct file_info));
129 err(1, "Couldn't malloc space for files descriptors.");
131 for (file = files; (fname = *argv++) != NULL; file++) {
132 file->file_name = strdup(fname);
133 if (! file->file_name)
134 errx(1, "Couldn't alloc space for file name.");
135 file->fp = fopen(file->file_name, "r");
136 if (file->fp == NULL ||
137 fstat(fileno(file->fp), &file->st) == -1) {
143 follow(files, style, off);
144 for (i = 0, file = files; i < no_files; i++, file++)
145 free(file->file_name);
148 for (i = 0; (fname = *argv++) != NULL; ++i) {
149 if ((fp = fopen(fname, "r")) == NULL ||
150 fstat(fileno(fp), &sb)) {
155 showfilename(i, fname);
156 (void)fflush(stdout);
160 reverse(fp, style, off, &sb);
162 forward(fp, style, off, &sb);
168 if (fstat(fileno(stdin), &sb)) {
174 * Determine if input is a pipe. 4.4BSD will set the SOCKET
175 * bit in the st_mode field for pipes. Fix this then.
177 if (lseek(fileno(stdin), (off_t)0, SEEK_CUR) == -1 &&
180 fflag = 0; /* POSIX.2 requires this. */
184 reverse(stdin, style, off, &sb);
186 forward(stdin, style, off, &sb);
192 * Tail's options are weird. First, -n10 is the same as -n-10, not
193 * -n+10. Second, the number options are 1 based and not offsets,
194 * so -n+1 is the first line, and -c-1 is the last byte. Third, the
195 * number options for the -r option specify the number of things that
196 * get displayed, not the starting point in the file. The one major
197 * incompatibility in this version as compared to historical versions
198 * is that the 'r' option couldn't be modified by the -lbc options,
199 * i.e. it was always done in lines. This version treats -rc as a
200 * number of characters in reverse order. Finally, the default for
201 * -r is the entire file, not 10 lines.
204 getarg(int units, enum STYLE forward_style, enum STYLE backward_style,
205 enum STYLE *style, int *style_set, off_t *off)
212 *off = strtoll(optarg, &p, 10) * units;
214 errx(1, "illegal offset -- %s", optarg);
219 *style = forward_style;
225 *style = backward_style;
233 * Convert the obsolete argument form into something that getopt can handle.
234 * This means that anything of the form [+-][0-9][0-9]*[lbc][Ffr] that isn't
235 * the option argument for a -b, -c or -n option gets converted.
238 obsolete(char **argv)
244 while ((ap = *++argv) != NULL) {
245 /* Return if "--" or not an option of any form. */
249 } else if (ap[1] == '-')
253 /* Old-style option. */
254 case '0': case '1': case '2': case '3': case '4':
255 case '5': case '6': case '7': case '8': case '9':
257 /* Malloc space for dash, new option and argument. */
259 if ((start = p = malloc(len + 3)) == NULL)
264 * Go to the end of the option argument. Save off any
265 * trailing options (-3lf) and translate any trailing
266 * output style characters.
269 if (*t == 'F' || *t == 'f' || *t == 'r') {
285 case '0': case '1': case '2': case '3': case '4':
286 case '5': case '6': case '7': case '8': case '9':
290 errx(1, "illegal option -- %s", *argv);
298 * Options w/ arguments, skip the argument and continue
299 * with the next option.
307 /* Options w/o arguments, continue with the next option. */
313 /* Illegal option, return and let getopt handle it. */
323 (void)fprintf(stderr,
324 "usage: tail [-F | -f | -r] [-b # | -c # | -n #] [file ...]\n");