diff options
| -rw-r--r-- | usr.bin/head/head.1 | 5 | ||||
| -rw-r--r-- | usr.bin/head/head.c | 52 |
2 files changed, 49 insertions, 8 deletions
diff --git a/usr.bin/head/head.1 b/usr.bin/head/head.1 index 2e47515..a85c93f 100644 --- a/usr.bin/head/head.1 +++ b/usr.bin/head/head.1 @@ -40,11 +40,14 @@ .Sh SYNOPSIS .Nm head .Op Fl n Ar count +.Op Fl c Ar bytes .Op Ar file ... .Sh DESCRIPTION This filter displays the first .Ar count -lines of each of the specified files, or of the standard input if no +lines or +.Ar bytes +of each of the specified files, or of the standard input if no files are specified. If .Ar count diff --git a/usr.bin/head/head.c b/usr.bin/head/head.c index 3e5bf04..e4a7a58 100644 --- a/usr.bin/head/head.c +++ b/usr.bin/head/head.c @@ -58,6 +58,7 @@ static char sccsid[] = "@(#)head.c 8.2 (Berkeley) 5/4/95"; void err __P((int, const char *, ...)); void head __P((FILE *, int)); +void head_bytes __P((FILE *, int)); void obsolete __P((char *[])); void usage __P((void)); @@ -70,13 +71,17 @@ main(argc, argv) { register int ch; FILE *fp; - int first, linecnt; + int first, linecnt = -1, bytecnt = -1; char *ep; obsolete(argv); - linecnt = 10; - while ((ch = getopt(argc, argv, "n:")) != -1) + while ((ch = getopt(argc, argv, "n:c:")) != -1) switch(ch) { + case 'c': + bytecnt = strtol(optarg, &ep, 10); + if (*ep || bytecnt <= 0) + err(1, "illegal byte count -- %s", optarg); + break; case 'n': linecnt = strtol(optarg, &ep, 10); if (*ep || linecnt <= 0) @@ -89,7 +94,11 @@ main(argc, argv) argc -= optind; argv += optind; - if (*argv) + if (linecnt != -1 && bytecnt != -1) + err(1, "can't combine line and byte counts"); + if (linecnt == -1 ) + linecnt = 10; + if (*argv) { for (first = 1; *argv; ++argv) { if ((fp = fopen(*argv, "r")) == NULL) { err(0, "%s: %s", *argv, strerror(errno)); @@ -100,11 +109,18 @@ main(argc, argv) first ? "" : "\n", *argv); first = 0; } - head(fp, linecnt); + if (bytecnt == -1) + head(fp, linecnt); + else + head_bytes(fp, bytecnt); (void)fclose(fp); } - else + } + else if (bytecnt == -1) head(stdin, linecnt); + else + head_bytes(stdin, bytecnt); + exit(eval); } @@ -124,12 +140,34 @@ head(fp, cnt) } void +head_bytes(fp, cnt) + FILE *fp; + register int cnt; +{ + char buf[4096]; + register int readlen; + + while (cnt) { + if (cnt < sizeof(buf)) + readlen = cnt; + else + readlen = sizeof(buf); + readlen = fread(buf, sizeof(char), readlen, fp); + if (readlen == EOF) + break; + if (fwrite(buf, sizeof(char), readlen, stdout) != readlen) + err(1, "stdout: %s", strerror(errno)); + cnt -= readlen; + } +} + +void obsolete(argv) char *argv[]; { char *ap; - while (ap = *++argv) { + while ((ap = *++argv)) { /* Return if "--" or not "-[0-9]*". */ if (ap[0] != '-' || ap[1] == '-' || !isdigit(ap[1])) return; |
