root / prex-0.9.0 / usr / bin / head / head.c @ 03e9c04a
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/*
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* Copyright (c) 1980, 1987, 1992, 1993
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* The Regents of the University of California. All rights reserved.
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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. 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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#include <sys/types.h> |
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#include <ctype.h> |
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#include <err.h> |
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#include <errno.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 <unistd.h> |
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/*
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* head - give the first few lines of a stream or of each of a set of files
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*
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* Bill Joy UCB August 24, 1977
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*/
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#ifdef CMDBOX
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#define main(argc, argv) head_main(argc, argv)
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#endif
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void head(FILE *, int); |
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static void usage(void); |
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int eval;
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int
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main(int argc, char *argv[]) |
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{ |
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int ch;
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FILE *fp; |
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int first, linecnt;
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char *ep;
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linecnt = 10;
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while ((ch = getopt(argc, argv, "n:")) != EOF) |
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switch(ch) {
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case 'n': |
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linecnt = strtol(optarg, &ep, 10);
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if (*ep || linecnt <= 0) |
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err(1, "illegal line count -- %s", optarg); |
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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 (*argv)
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for (first = 1; *argv; ++argv) { |
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if ((fp = fopen(*argv, "r")) == NULL) { |
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err(0, "%s: %s", *argv, strerror(errno)); |
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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", *argv); |
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first = 0;
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} |
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head(fp, linecnt); |
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(void)fclose(fp);
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} |
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else
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head(stdin, linecnt); |
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exit(eval); |
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} |
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void
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head(FILE *fp, int cnt)
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{ |
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int ch;
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while (cnt--)
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while ((ch = getc(fp)) != EOF) { |
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if (putchar(ch) == EOF) |
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err(1, "stdout: %s", strerror(errno)); |
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if (ch == '\n') |
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break;
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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, "usage: head [-n lines] [file ...]\n"); |
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exit(1);
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} |