Question

我正在用C编写一个命令行程序，我想实现一个--help选项来显示常用的东西，比如可用的选项和它们的用途以及用法示例。

是否有正确的方法来格式化帮助中显示的文本？或者我是否尽力让它看起来不错？

我查看了SourceForge上的一些随机程序，看看他们是如何做到的，并且大多数只使用了一堆printf()来输出预先格式化的（就间距和缩进而言）文本。

此处groff或troff是否合适？我在谷歌搜索中遇到过这些应用程序，它们似乎是某种排版程序，但我对它们并不熟悉。

Answer 1

一般来说，更多的人担心程序的工作方式与帮助显示的程度相同。使用printf尽力而为（努力永远受到赞赏）并继续使用它和您的生活。你有更大的鱼可以炒。

Answer 2

不要那么多格式化。另一方面，你自己会不时地使用它。包括诸如程序的目的，相关选项和一些示例等相关细节。清楚地描述它们的空白行应该是好的。

在不相关的说明中，如果您在c中执行命令行选项，请使用gnu getopts c库。它使它变得更容易。作为奖励，您不会被解析命令行的细节所困扰。

Answer 3

使用groff或troff是过度的。正确布局printf()格式就足够了。如果系统地布置帮助消息，则可以轻松管理。我在任何程序中使用的最复杂的选项包括：

static const char optlist[] = "a:cd:e:f:ghi:o:p:st:u:vxyz:A:BCD:E:F:G:HIJL:M:N:O:PQ:RS:TUVX:YZ:";

static const char usestr[] =
"[-cghsvxyY] [-d dbase] [-f file] [-e 'SQL stmt'] ['SQL stmt' ...]\n"
"Other options: [-CJPRU][-BHITV][-D delim][-E escape][-Q quote][-F format]\n"
"               [-A date][-i file][-o file][-L qlimit][-N number][-M FIFO]\n"
"               [-Z debug][-G eor][-t table][-p password][-u username]\n"
"               [-a ibase][-X record=rectag,recset=settag,header=hdrtag]\n"
"               [-O orderby][-S skip][-z number]\n"
"NB: -h gives more help!";

static const char fullhelp[] =
"\nOption summary:\n"
"   -a ibase      - input base (default 0; set to 10 for fields with leading zeroes)\n"
"   -c            - continue after errors\n"
"   -d dbase      - select database\n"
"   -e 'SQL stmt' - execute SQL command\n"
"   -f file       - input file for SQLCMD\n"
"   -g            - debugging mode (single-step commands)\n"
"   -h            - print this message\n"
"   -i file       - input file for SQLRELOAD\n"
"   -o file       - output file for SQLUNLOAD\n"
"   -p password   - password for connection (beware security implications!)\n"
"   -s            - silent mode\n"
"   -t table      - name of table (for SQLRELOAD or SQLUNLOAD)\n"
"   -u username   - username for connection (beware security implications!)\n"
"   -v            - verbose mode\n"
"   -x            - trace mode\n"
"   -y            - enable history\n"
"   -z number     - set debugging level for syntax and lexical analyzers\n"
"   -A date       - set date format (eg dd-mm-yyyy for $DBDATE=dmy4-)\n"
"   -B            - operate in benchmark mode (implies -x and times SQL)\n"
"   -C            - operate as SQLCMD\n"
"   -D delim      - set field delimiter (default $DBDELIMITER or pipe)\n"
"   -E escape     - set escape character (default $DBESCAPE or backslash)\n"
"   -F format     - set output format (default SELECT; alternatives include:\n"
"                   UNLOAD, FIXED, FIXSEP, FIXDEL, CSV, XML, HTML)\n"
"   -G eor        - set EOR (end of record) character string (default $DBNEWLINE or newline)\n"
"   -H            - include column headings in output\n"
"   -I            - interactive mode (after executing command line)\n"
"   -J            - simulate isql/dbaccess; accept [database|-] [script|-]\n"
"   -L qlimit     - limit on number of rows returned by query\n"
"   -M FIFO       - monitor FIFO for input commands\n"
"   -N number     - size of transaction under RELOAD\n"
"                   (default 1024; 0 means no sub-transactions)\n"
"   -O col1,...   - order by these columns (SQLUNLOAD)\n"
"   -P            - operate as SQLUPLOAD (not implemented yet)\n"
"   -Q quote      - set quote character (default $DBQUOTE or double quote)\n"
"   -R            - operate as SQLRELOAD\n"
"   -S skip       - initial rows to skip (SQLRELOAD)\n"
"   -T            - include column types in output\n"
"   -U            - operate as SQLUNLOAD\n"
"   -V            - print version and exit\n"
"   -X xmloptions - configure the XML output\n"
"      recset='recsettag',record='recordtag',header='headertag'\n"
"   -Y            - do not enable history, even in interactive mode\n"
"   -Z debug      - set debugging level (SQLCMD must be compiled with debugging enabled)\n"
;

是的，它不久就需要长期选择。

正确格式化--help输出

3 个答案: