diff options
Diffstat (limited to 'usr.bin/head/head.c')
| -rw-r--r-- | usr.bin/head/head.c | 180 |
1 files changed, 180 insertions, 0 deletions
diff --git a/usr.bin/head/head.c b/usr.bin/head/head.c new file mode 100644 index 0000000..e33a3c2 --- /dev/null +++ b/usr.bin/head/head.c @@ -0,0 +1,180 @@ +/* + * Copyright (c) 1980, 1987, 1992, 1993 + * The Regents of the University of California. All rights reserved. + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions + * are met: + * 1. Redistributions of source code must retain the above copyright + * notice, this list of conditions and the following disclaimer. + * 2. Redistributions in binary form must reproduce the above copyright + * notice, this list of conditions and the following disclaimer in the + * documentation and/or other materials provided with the distribution. + * 3. All advertising materials mentioning features or use of this software + * must display the following acknowledgement: + * This product includes software developed by the University of + * California, Berkeley and its contributors. + * 4. Neither the name of the University nor the names of its contributors + * may be used to endorse or promote products derived from this software + * without specific prior written permission. + * + * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND + * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE + * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE + * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE + * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL + * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS + * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) + * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT + * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY + * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF + * SUCH DAMAGE. + */ + +#ifndef lint +static char copyright[] = +"@(#) Copyright (c) 1980, 1987, 1992, 1993\n\ + The Regents of the University of California. All rights reserved.\n"; +#endif /* not lint */ + +#ifndef lint +static char sccsid[] = "@(#)head.c 8.1 (Berkeley) 6/6/93"; +#endif /* not lint */ + +#include <sys/types.h> +#include <errno.h> +#include <stdlib.h> +#include <string.h> +#include <stdio.h> +#include <ctype.h> + +/* + * head - give the first few lines of a stream or of each of a set of files + * + * Bill Joy UCB August 24, 1977 + */ + +void err __P((int, const char *, ...)); +void head __P((FILE *, int)); +void obsolete __P((char *[])); +void usage __P((void)); + +int eval; + +int +main(argc, argv) + int argc; + char *argv[]; +{ + register int ch; + FILE *fp; + int first, linecnt; + char *ep; + + obsolete(argv); + linecnt = 10; + while ((ch = getopt(argc, argv, "n:")) != EOF) + switch(ch) { + case 'n': + linecnt = strtol(optarg, &ep, 10); + if (*ep || linecnt <= 0) + err(1, "illegal line count -- %s", optarg); + break; + case '?': + default: + usage(); + } + argc -= optind; + argv += optind; + + if (*argv) + for (first = 1; *argv; ++argv) { + if ((fp = fopen(*argv, "r")) == NULL) { + err(0, "%s: %s", *argv, strerror(errno)); + continue; + } + if (argc > 1) { + (void)printf("%s==> %s <==\n", + first ? "" : "\n", *argv); + first = 0; + } + head(fp, linecnt); + (void)fclose(fp); + } + else + head(stdin, linecnt); + exit(eval); +} + +void +head(fp, cnt) + FILE *fp; + register int cnt; +{ + register int ch; + + while (cnt--) + while ((ch = getc(fp)) != EOF) { + if (putchar(ch) == EOF) + err(1, "stdout: %s", strerror(errno)); + if (ch == '\n') + break; + } +} + +void +obsolete(argv) + char *argv[]; +{ + char *ap; + + while (ap = *++argv) { + /* Return if "--" or not "-[0-9]*". */ + if (ap[0] != '-' || ap[1] == '-' || !isdigit(ap[1])) + return; + if ((ap = malloc(strlen(*argv) + 2)) == NULL) + err(1, "%s", strerror(errno)); + ap[0] = '-'; + ap[1] = 'n'; + (void)strcpy(ap + 2, *argv + 1); + *argv = ap; + } +} + +void +usage() +{ + (void)fprintf(stderr, "usage: head [-n lines] [file ...]\n"); + exit(1); +} + +#if __STDC__ +#include <stdarg.h> +#else +#include <varargs.h> +#endif + +void +#if __STDC__ +err(int fatal, const char *fmt, ...) +#else +err(fatal, fmt, va_alist) + int fatal; + char *fmt; + va_dcl +#endif +{ + va_list ap; +#if __STDC__ + va_start(ap, fmt); +#else + va_start(ap); +#endif + (void)fprintf(stderr, "head: "); + (void)vfprintf(stderr, fmt, ap); + va_end(ap); + (void)fprintf(stderr, "\n"); + if (fatal) + exit(1); + eval = 1; +} |
