简单的CLI(command line interface)

本文主要是介绍简单的CLI(command line interface)，希望对大家解决编程问题提供一定的参考价值，需要的开发者们随着小编来一起学习吧！

一、简介

CLI（command line interface）是系统为用户提供的命令行接口。相信熟悉linux的同学肯定都必须了解一些linux的命令，在linux的shell上运行以实现一些功能。如最简单的ls命令，显示目录内容。

CLI可以让用户实时的与系统进行交互，获取系统的实时信息，完成用户自定义的功能。所有的系统都必须为用户提供接口，只不过接口的形式多种多样，如web、传统的C/S结构的图像界面，当然CLI是其中的一种方式。

二、为什么要研究CLI

你在做项目（主要指C/C++项目）的时候是否遇到过如下问题：

1、程序运行过程中出现故障，想实时的查看一些运行状态；

2、需要实时的与运行的系统进行一些简单的交互；

3、遇到这些问题时，你又不想使用GDB跟踪；

这时可以考虑为自己的程序增加一个小小的CLI，会极大的方便你的开发。

问题来了，实现像linux 强大CLI系统，那可不是一件简单的事情。如果从零DIY一个自己的CLI感觉有点困难，这时软件复用就派上用场了。只要你可以找一个已有的项目，带CLI的将其移植一下，相信很快就可以为你的程序添加一个属于你自己私有的CLI。自定义一下命令，不需要华丽的用户体验，只要实用即可。

三、自己的CLI

当时我想到的简单CLI就是uboot，熟悉uboot的同学肯定都知道uboot有一套命令集，如果做过uboot移植的同学肯定经常用它。只需要几个命令就可以将linux kernel引导起来，非常实用。那很自然的如果将uboot这套CLI移植到你的程序中，自定义一下适合自己的命令，那就大功告成了。

那就废话少说，看看uboot源码，将CLI部分移植出来。

下面是本人从uboot中移植的代码：

1、很简单只有两个文件（command.h和command.c）；

2、将这两个文件编译一下：如gcc command.c -o ct，然后直接执行./ct；

3、下面是测试结果

源码：command.h

#ifndef __COMMAND_H__
#define __COMMAND_H__/* Monitor Command Prompt */
#define CONFIG_SYS_PROMPT "->"/* Buffer size for input from the Console */
#define CONFIG_SYS_CBSIZE		256#endif

源码：command.c

#include <stdio.h>
#include <stdlib.h>
#include <stdint.h>#include "command.h"#define MAX_ARGC 10#define MAX_CMD_NUM 50uint8_t console_buffer[CONFIG_SYS_CBSIZE + 1];	/* console I/O buffer	*/
static char erase_seq[] = "\b \b";		/* erase sequence	*/
static char   tab_seq[] = "        ";		/* used to expand TABs	*/typedef void (*cmd_fun_t)(int , char *[])  ;
//命令结构体 
typedef struct CMD_STRUCT
{ char name[32]; /* Command Name */ char usage[64];/* Usage message */ cmd_fun_t CmdFun;//void (*CmdFun)(int , char *[]);/* Command execute function */ 
}CMD_STRUCT_T; int cmd_num_current = 0;//命令列表 
CMD_STRUCT_T CmdTbl[MAX_CMD_NUM]; #ifdef debug_cmd
#define debug_print() printf("[%s] line:%d\n", __FUNCTION__, __LINE__)
#else
#define debug_print() 
#endifvoid HelpCmdExeFun(int agrc, char *argv[])
{
debug_print() ;int i = 0;while (i < cmd_num_current){printf("%3d. %-32s -- %s\n", i, CmdTbl[i].name,  CmdTbl[i].usage);i++;}return; }void read_fun(int agrc, char * argv [ ])
{
debug_print() ;int i = 0;while (i < cmd_num_current) {if (read_fun == CmdTbl[i].CmdFun){printf("%s -- %s\n", CmdTbl[i].name,  CmdTbl[i].usage);break;}i++;}return; 
}void write_fun(int agrc, char * argv [ ])
{
debug_print() ;int i = 0;while (i < cmd_num_current) {if (write_fun == CmdTbl[i].CmdFun){printf("%s -- %s\n", CmdTbl[i].name,  CmdTbl[i].usage);break;}i++;}return; 
}void setenv_fun(int agrc, char * argv [ ])
{
debug_print() ;int i = 0;while (i < cmd_num_current) {if (setenv_fun == CmdTbl[i].CmdFun){printf("%s -- %s\n", CmdTbl[i].name,  CmdTbl[i].usage);break;}i++;}return; 
}int register_cmd(char *name, char *usage, cmd_fun_t fun)
{int ret;if (cmd_num_current < MAX_CMD_NUM){strcpy(CmdTbl[cmd_num_current].name, name);strcpy(CmdTbl[cmd_num_current].usage , usage);CmdTbl[cmd_num_current].CmdFun = fun;cmd_num_current++;}else{printf("%s error\n");return 1;}return 0;
}char parse_buf[256] ;
int parse_line(const char * const line, char *argv[])
{
debug_print();int argc = 0;char *ptr = parse_buf;memset(parse_buf, '\0', 256);strncpy(parse_buf, line, strlen(line));while ((argv[argc]=strtok(ptr, " "))!=NULL){
debug_print();
//printf("argv[%d]:%s\n", argc, argv[argc]);argc++;if (argc > MAX_ARGC)break;ptr = NULL;}
debug_print();return argc;
}static char * delete_char (char *buffer, char *p, int *colp, int *np, int plen)
{char *s;if (*np == 0) {return (p);}if (*(--p) == '\t') {			/* will retype the whole line	*/while (*colp > plen) {puts (erase_seq);(*colp)--;}for (s=buffer; s<p; ++s) {if (*s == '\t') {puts (tab_seq+((*colp) & 07));*colp += 8 - ((*colp) & 07);} else {++(*colp);putc (*s, stdout );}}} else {puts (erase_seq);(*colp)--;}(*np)--;return (p);
}int32_t readline_into_buffer ( int8_t *const prompt, int8_t * buffer)
{int8_t *p = buffer;int8_t * p_buf = p;int32_t n = 0;				/* buffer index		*/int32_t plen = 0;			/* prompt length	*/int32_t col;				/* output column cnt	*/int8_t c;int8_t *ptr = prompt;/* print prompt */if (prompt) {plen = strlen (prompt);while (*ptr)putc(*ptr++, stdout);//puts (prompt);}col = plen;while (1){c = getc(stdin);/** Special character handling*/switch (c) {case '\r':				/* Enter		*/case '\n':*p = '\0';//puts ("\r");return (p - p_buf);case '\0':				/* nul			*/continue;case 0x03:				/* ^C - break		*/p_buf[0] = '\0';	/* discard input */return (-1);case 0x15:				/* ^U - erase line	*/while (col > plen) {puts (erase_seq);--col;}p = p_buf;n = 0;continue;case 0x17:				/* ^W - erase word	*/p=delete_char(p_buf, p, &col, &n, plen);while ((n > 0) && (*p != ' ')) {p=delete_char(p_buf, p, &col, &n, plen);}continue;case 0x08:				/* ^H  - backspace	*/case 0x7F:				/* DEL - backspace	*/p=delete_char(p_buf, p, &col, &n, plen);continue;default:/** Must be a normal character then*/if (n < CONFIG_SYS_CBSIZE-2){if (c == '\t') {	/* expand TABs		*///puts (tab_seq+(col&07));col += 8 - (col&07);} else{++col;		/* echo input		*///putc (c, stdout);}*p++ = c;++n;} else {			/* Buffer full		*/putc ('\a', stdout);}}}}int32_t readline ( int8_t *const prompt)
{/** If console_buffer isn't 0-length the user will be prompted to modify* it instead of entering it from scratch as desired.*/memset(console_buffer, '\0', CONFIG_SYS_CBSIZE+1);console_buffer[0] = '\0';return readline_into_buffer(prompt, console_buffer);
}int find_cmd(char *cmd)
{
debug_print();
//printf("cmd:%s\n",cmd);int cmd_index = 0;if (('0' == cmd[0]) && ('\0' == cmd[1]))return cmd_index;cmd_index = atoi(cmd);if ((cmd_index >0 ) && (cmd_index < cmd_num_current)){return cmd_index;}cmd_index = 0;while (cmd_index < MAX_CMD_NUM){if (0 == strncmp(CmdTbl[cmd_index].name, cmd, strlen(cmd)))return cmd_index;cmd_index++;}printf("Command  [%s ]  don't support!\n", cmd);debug_print();return -1 ;
}
/***************************************************************************** returns:*	1  - command executed, repeatable*	0  - command executed but not repeatable, interrupted commands are*	     always considered not repeatable*	-1 - not executed (unrecognized, bootd recursion or too many args)*           (If cmd is NULL or "" or longer than CONFIG_SYS_CBSIZE-1 it is*           considered unrecognized)** WARNING:** We must create a temporary copy of the command since the command we get* may be the result from getenv(), which returns a pointer directly to* the environment data, which may change magicly when the command we run* creates or modifies environment variables (like "bootp" does).*/
int run_command (const char * const cmd, int flag)
{
debug_print();//puts(cmd);int cmd_index = 0;int argc = 0;char *argv[MAX_ARGC];argc = parse_line(cmd, argv);if ((argc > 0) &&(argc < MAX_ARGC))cmd_index = find_cmd(argv[0]);elsereturn 1;if ( -1 != cmd_index)CmdTbl[cmd_index].CmdFun(argc, argv);debug_print();return 0;#if 0cmd_tbl_t *cmdtp;char cmdbuf[CONFIG_SYS_CBSIZE];	/* working copy of cmd		*/char *token;			/* start of token in cmdbuf	*/char *sep;			/* end of token (separator) in cmdbuf */char finaltoken[CONFIG_SYS_CBSIZE];char *str = cmdbuf;char *argv[CONFIG_SYS_MAXARGS + 1];	/* NULL terminated	*/int argc, inquotes;int repeatable = 1;int rc = 0;#ifdef DEBUG_PARSERprintf ("[RUN_COMMAND] cmd[%p]=\"", cmd);puts (cmd ? cmd : "NULL");	/* use puts - string may be loooong */puts ("\"\n");
#endifclear_ctrlc();		/* forget any previous Control C */if (!cmd || !*cmd) {return -1;	/* empty command */}if (strlen(cmd) >= CONFIG_SYS_CBSIZE) {puts ("## Command too long!\n");return -1;}strcpy (cmdbuf, cmd);/* Process separators and check for invalid* repeatable commands*/#ifdef DEBUG_PARSERprintf ("[PROCESS_SEPARATORS] %s\n", cmd);
#endifwhile (*str) {/** Find separator, or string end* Allow simple escape of ';' by writing "\;"*/for (inquotes = 0, sep = str; *sep; sep++) {if ((*sep=='\'') &&(*(sep-1) != '\\'))inquotes=!inquotes;if (!inquotes &&(*sep == ';') &&	/* separator		*/( sep != str) &&	/* past string start	*/(*(sep-1) != '\\'))	/* and NOT escaped	*/break;}/** Limit the token to data between separators*/token = str;if (*sep) {str = sep + 1;	/* start of command for next pass */*sep = '\0';}elsestr = sep;	/* no more commands for next pass */
#ifdef DEBUG_PARSERprintf ("token: \"%s\"\n", token);
#endif/* find macros in this token and replace them */process_macros (token, finaltoken);/* Extract arguments */if ((argc = parse_line (finaltoken, argv)) == 0) {rc = -1;	/* no command at all */continue;}/* Look up command in command table */if ((cmdtp = find_cmd(argv[0])) == NULL) {printf ("Unknown command '%s' - try 'help'\n", argv[0]);rc = -1;	/* give up after bad command */continue;}/* found - check max args */if (argc > cmdtp->maxargs) {cmd_usage(cmdtp);rc = -1;continue;}#if defined(CONFIG_CMD_BOOTD)/* avoid "bootd" recursion */if (cmdtp->cmd == do_bootd) {
#ifdef DEBUG_PARSERprintf ("[%s]\n", finaltoken);
#endifif (flag & CMD_FLAG_BOOTD) {puts ("'bootd' recursion detected\n");rc = -1;continue;} else {flag |= CMD_FLAG_BOOTD;}}
#endif/* OK - call function to do the command */if ((cmdtp->cmd) (cmdtp, flag, argc, argv) != 0) {rc = -1;}repeatable &= cmdtp->repeatable;/* Did the user stop this? */if (had_ctrlc ())return -1;	/* if stopped then not repeatable */}return rc ? rc : repeatable;#endif
}int main(int argc, char **argv)
{int32_t rc = -1;int32_t len;static int8_t lastcommand[CONFIG_SYS_CBSIZE] = { 0, };memset(CmdTbl, 0, sizeof(CMD_STRUCT_T)*MAX_CMD_NUM);register_cmd("help", "list all cmd\n\r",       HelpCmdExeFun);register_cmd("read", "read memory\n\r",    read_fun);register_cmd("write", "write memory\n\r",  write_fun);register_cmd("setenv", "set env\n\r",        setenv_fun);debug_print();while (1){len = readline (CONFIG_SYS_PROMPT);if (len > 0){memset(lastcommand, '\0', CONFIG_SYS_CBSIZE);strncpy (lastcommand, console_buffer, strlen(console_buffer));rc = run_command (lastcommand, 0);if (rc <= 0){/* invalid command or not repeatable, forget it */lastcommand[0] = 0;}}}return 0;
}