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Diffstat (limited to 'usr/src/lib/libcmd/common/head.c')
| -rw-r--r-- | usr/src/lib/libcmd/common/head.c | 150 |
1 files changed, 150 insertions, 0 deletions
diff --git a/usr/src/lib/libcmd/common/head.c b/usr/src/lib/libcmd/common/head.c new file mode 100644 index 0000000000..707d0478a8 --- /dev/null +++ b/usr/src/lib/libcmd/common/head.c @@ -0,0 +1,150 @@ +/*********************************************************************** +* * +* This software is part of the ast package * +* Copyright (c) 1992-2007 AT&T Knowledge Ventures * +* and is licensed under the * +* Common Public License, Version 1.0 * +* by AT&T Knowledge Ventures * +* * +* A copy of the License is available at * +* http://www.opensource.org/licenses/cpl1.0.txt * +* (with md5 checksum 059e8cd6165cb4c31e351f2b69388fd9) * +* * +* Information and Software Systems Research * +* AT&T Research * +* Florham Park NJ * +* * +* Glenn Fowler <gsf@research.att.com> * +* David Korn <dgk@research.att.com> * +* * +***********************************************************************/ +#pragma prototyped +/* + * David Korn + * AT&T Bell Laboratories + * + * output the beginning portion of one or more files + */ + +static const char usage[] = +"[-?\n@(#)$Id: head (AT&T Research) 2006-09-27 $\n]" +USAGE_LICENSE +"[+NAME?head - output beginning portion of one or more files ]" +"[+DESCRIPTION?\bhead\b copies one or more input files to standard " + "output stopping at a designated point for each file or to the end of " + "the file whichever comes first. Copying ends at the point indicated by " + "the options. By default a header of the form \b==> \b\afilename\a\b " + "<==\b is output before all but the first file but this can be changed " + "with the \b-q\b and \b-v\b options.]" +"[+?If no \afile\a is given, or if the \afile\a is \b-\b, \bhead\b " + "copies from standard input starting at the current location.]" +"[+?The option argument for \b-c\b, and \b-s\b can optionally be " + "followed by one of the following characters to specify a different unit " + "other than a single byte:]" + "{" + "[+b?512 bytes.]" + "[+k?1-killobyte.]" + "[+m?1-megabyte.]" + "}" +"[+?For backwards compatibility, \b-\b\anumber\a is equivalent to \b-n\b " + "\anumber\a.]" +"[n:lines?Copy \alines\a lines from each file.]#[lines:=10]" +"[c:bytes?Copy \achars\a bytes from each file.]#[chars]" +"[q:quiet|silent?Never ouput filename headers.]" +"[s:skip?Skip \askip\a characters or lines from each file before " + "copying.]#[skip]" +"[v:verbose?Always ouput filename headers.]" + "\n\n" +"[ file ... ]" + "\n\n" +"[+EXIT STATUS?]" + "{" + "[+0?All files copied successfully.]" + "[+>0?One or more files did not copy.]" + "}" +"[+SEE ALSO?\bcat\b(1), \btail\b(1)]" +; + +#include <cmd.h> + +int +b_head(int argc, register char** argv, void* context) +{ + static const char header_fmt[] = "\n==> %s <==\n"; + + register Sfio_t* fp; + register char* cp; + register off_t keep = 10; + register off_t skip = 0; + register int delim = '\n'; + int header = 1; + char* format = (char*)header_fmt+1; + + cmdinit(argc, argv, context, ERROR_CATALOG, 0); + for (;;) + { + switch (optget(argv, usage)) + { + case 'c': + delim = -1; + /*FALLTHROUGH*/ + case 'n': + if (opt_info.offset && argv[opt_info.index][opt_info.offset] == 'c') + { + delim = -1; + opt_info.offset++; + } + if ((keep = opt_info.number) <=0) + error(2, "%s: %I*d: positive numeric option argument expected", opt_info.name, sizeof(keep), keep); + continue; + case 'q': + header = argc; + continue; + case 'v': + header = 0; + continue; + case 's': + skip = opt_info.number; + continue; + case '?': + error(ERROR_usage(2), "%s", opt_info.arg); + continue; + case ':': + error(2, "%s", opt_info.arg); + continue; + } + break; + } + argv += opt_info.index; + argc -= opt_info.index; + if (error_info.errors) + error(ERROR_usage(2), "%s", optusage(NiL)); + if (cp = *argv) + argv++; + do + { + if (!cp || streq(cp, "-")) + { + cp = "/dev/stdin"; + fp = sfstdin; + sfset(fp, SF_SHARE, 1); + } + else if (!(fp = sfopen(NiL, cp, "r"))) + { + error(ERROR_system(0), "%s: cannot open", cp); + continue; + } + if (argc > header) + sfprintf(sfstdout, format, cp); + format = (char*)header_fmt; + if (skip > 0) + sfmove(fp, NiL, skip, delim); + if (sfmove(fp, sfstdout, keep, delim) < 0 && errno != EPIPE) + error(ERROR_system(0), "%s: read error", cp); + if (fp != sfstdin) + sfclose(fp); + } while (cp = *argv++); + if (sfsync(sfstdout)) + error(ERROR_system(0), "write error"); + return error_info.errors != 0; +} |