編程實現linux下的shell

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/*************************************************************************    > File Name: Kris_shell.c    > Author: KrisChou    > Mail:[email protected]     > Created Time: Thu 21 Aug 2014 04:31:55 PM CST ************************************************************************/#include <stdio.h>#include <stdlib.h>#include <string.h>#include <sys/types.h>#include <sys/stat.h>#include <unistd.h>#include <sys/wait.h>#define PROMPT ">>" #define ARG_CNT 32void command_to_arglist(char** arglist,char *cmd_line);

int main(int argc, char *argv[]){    char cmd_line[1024];    char *arglist[ARG_CNT];    while(memset(cmd_line,0,1024), printf("%s",PROMPT), fgets(cmd_line,1024,stdin))    {        if(cmd_line[0] != ‘\n‘)        {            cmd_line[strlen(cmd_line) - 1] = ‘\0‘; //將讀進來的分行符號變成‘\0‘            command_to_arglist(arglist,cmd_line);            if(fork() > 0)            {                wait(NULL);            }else            {                execvp(arglist[0],arglist);                exit(0);            }        }    }    return 0;}static int my_isspace(char c){    if(c == ‘ ‘|| c == ‘\n‘ || c == ‘\t‘ || c ==‘\v‘)        return 1;    else        return 0;}

static void command_to_arglist(char** arglist,char *cmd_line){    int cnt = 0;    int bg,end;    bg = 0;    while(cmd_line[bg] != ‘\0‘)    {        while(my_isspace(cmd_line[bg]))        {            bg++;        }        if(cmd_line[bg] == ‘\0‘)        {            break;        }        end = bg;        while(cmd_line[end] != ‘\0‘ && !my_isspace(cmd_line[end]))        {            end++;        }        arglist[cnt] = (char*)calloc(1, (end-bg+1));        strncpy(arglist[cnt],cmd_line+bg,(end-bg));        cnt++;        bg = end;    }    arglist[cnt] = NULL;    }