304 lines
7.4 KiB
C
304 lines
7.4 KiB
C
/*-
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* Copyright (c) 1991, 1993
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* The Regents of the University of California. All rights reserved.
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*
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* This code is derived from software contributed to Berkeley by
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* Edward Sze-Tyan Wang.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. All advertising materials mentioning features or use of this software
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* must display the following acknowledgement:
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* This product includes software developed by the University of
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* California, Berkeley and its contributors.
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* 4. Neither the name of the University nor the names of its contributors
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* may be used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*/
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#ifndef lint
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static char copyright[] =
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"@(#) Copyright (c) 1991, 1993\n\
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The Regents of the University of California. All rights reserved.\n";
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#endif /* not lint */
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#ifndef lint
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static char sccsid[] = "@(#)tail.c 8.1 (Berkeley) 6/6/93";
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#endif /* not lint */
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#include <sys/types.h>
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#include <sys/stat.h>
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#include <errno.h>
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#include <unistd.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include <err.h>
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#include "extern.h"
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int fflag, rflag, rval;
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char *fname;
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static void obsolete __P((char **));
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static void usage __P((void));
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int
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main(argc, argv)
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int argc;
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char *argv[];
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{
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struct stat sb;
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FILE *fp;
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long off;
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enum STYLE style;
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int ch, first;
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char *p;
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/*
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* Tail's options are weird. First, -n10 is the same as -n-10, not
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* -n+10. Second, the number options are 1 based and not offsets,
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* so -n+1 is the first line, and -c-1 is the last byte. Third, the
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* number options for the -r option specify the number of things that
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* get displayed, not the starting point in the file. The one major
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* incompatibility in this version as compared to historical versions
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* is that the 'r' option couldn't be modified by the -lbc options,
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* i.e. it was always done in lines. This version treats -rc as a
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* number of characters in reverse order. Finally, the default for
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* -r is the entire file, not 10 lines.
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*/
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#define ARG(units, forward, backward) { \
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if (style) \
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usage(); \
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off = strtol(optarg, &p, 10) * (units); \
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if (*p) \
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errx(1, "illegal offset -- %s", optarg); \
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switch(optarg[0]) { \
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case '+': \
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if (off) \
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off -= (units); \
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style = (forward); \
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break; \
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case '-': \
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off = -off; \
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/* FALLTHROUGH */ \
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default: \
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style = (backward); \
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break; \
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} \
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}
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obsolete(argv);
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style = NOTSET;
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while ((ch = getopt(argc, argv, "b:c:fn:r")) != -1)
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switch(ch) {
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case 'b':
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ARG(512, FBYTES, RBYTES);
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break;
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case 'c':
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ARG(1, FBYTES, RBYTES);
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break;
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case 'f':
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fflag = 1;
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break;
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case 'n':
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ARG(1, FLINES, RLINES);
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break;
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case 'r':
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rflag = 1;
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break;
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case '?':
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default:
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usage();
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}
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argc -= optind;
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argv += optind;
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if (fflag && argc > 1)
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errx(1, "-f option only appropriate for a single file");
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/*
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* If displaying in reverse, don't permit follow option, and convert
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* style values.
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*/
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if (rflag) {
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if (fflag)
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usage();
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if (style == FBYTES)
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style = RBYTES;
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else if (style == FLINES)
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style = RLINES;
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}
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/*
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* If style not specified, the default is the whole file for -r, and
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* the last 10 lines if not -r.
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*/
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if (style == NOTSET)
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if (rflag) {
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off = 0;
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style = REVERSE;
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} else {
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off = 10;
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style = RLINES;
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}
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if (*argv)
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for (first = 1; fname = *argv++;) {
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if ((fp = fopen(fname, "r")) == NULL ||
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fstat(fileno(fp), &sb)) {
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ierr();
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continue;
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}
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if (argc > 1) {
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(void)printf("%s==> %s <==\n",
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first ? "" : "\n", fname);
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first = 0;
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(void)fflush(stdout);
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}
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if (rflag)
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reverse(fp, style, off, &sb);
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else
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forward(fp, style, off, &sb);
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(void)fclose(fp);
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}
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else {
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fname = "stdin";
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if (fstat(fileno(stdin), &sb)) {
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ierr();
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exit(1);
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}
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/*
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* Determine if input is a pipe. 4.4BSD will set the SOCKET
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* bit in the st_mode field for pipes. Fix this then.
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*/
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if (lseek(fileno(stdin), (off_t)0, SEEK_CUR) == -1 &&
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errno == ESPIPE) {
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errno = 0;
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fflag = 0; /* POSIX.2 requires this. */
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}
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if (rflag)
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reverse(stdin, style, off, &sb);
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else
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forward(stdin, style, off, &sb);
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}
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exit(rval);
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}
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/*
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* Convert the obsolete argument form into something that getopt can handle.
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* This means that anything of the form [+-][0-9][0-9]*[lbc][fr] that isn't
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* the option argument for a -b, -c or -n option gets converted.
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*/
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static void
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obsolete(argv)
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char *argv[];
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{
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register char *ap, *p, *t;
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int len;
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char *start;
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while (ap = *++argv) {
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/* Return if "--" or not an option of any form. */
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if (ap[0] != '-') {
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if (ap[0] != '+')
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return;
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} else if (ap[1] == '-')
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return;
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switch(*++ap) {
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/* Old-style option. */
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case '0': case '1': case '2': case '3': case '4':
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case '5': case '6': case '7': case '8': case '9':
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/* Malloc space for dash, new option and argument. */
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len = strlen(*argv);
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if ((start = p = malloc(len + 3)) == NULL)
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err(1, "malloc");
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*p++ = '-';
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/*
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* Go to the end of the option argument. Save off any
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* trailing options (-3lf) and translate any trailing
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* output style characters.
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*/
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t = *argv + len - 1;
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if (*t == 'f' || *t == 'r') {
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*p++ = *t;
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*t-- = '\0';
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}
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switch(*t) {
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case 'b':
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*p++ = 'b';
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*t = '\0';
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break;
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case 'c':
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*p++ = 'c';
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*t = '\0';
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break;
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case 'l':
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*t = '\0';
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/* FALLTHROUGH */
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case '0': case '1': case '2': case '3': case '4':
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case '5': case '6': case '7': case '8': case '9':
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*p++ = 'n';
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break;
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default:
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errx(1, "illegal option -- %s", *argv);
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}
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*p++ = *argv[0];
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(void)strcpy(p, ap);
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*argv = start;
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continue;
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/*
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* Options w/ arguments, skip the argument and continue
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* with the next option.
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*/
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case 'b':
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case 'c':
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case 'n':
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if (!ap[1])
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++argv;
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/* FALLTHROUGH */
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/* Options w/o arguments, continue with the next option. */
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case 'f':
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case 'r':
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continue;
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/* Illegal option, return and let getopt handle it. */
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default:
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return;
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}
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}
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}
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static void
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usage()
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{
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(void)fprintf(stderr,
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"usage: tail [-f | -r] [-b # | -c # | -n #] [file ...]\n");
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exit(1);
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}
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