simpleshell.c

linux 下模拟shell的实现。 支持管道等功能。读proc文件

#include <unistd.h>
#include <stdio.h>
#define MAX_CMD 100
int main()
{
	int pid;
	int i,j,k,len,tag;
	char cmd[10][10];
	char *argv[10]={NULL,NULL,NULL,NULL,NULL,NULL,NULL,NULL,NULL,NULL};
	char buffer[100];
	char *file;
	char* tip="kxz_shell# ";
	

	printf("Welcome to kxz_shell!\nDeveloped by Kong Xiangzhen 03055078 jsj33\n ");
again:
        for(i=0;i<10;i++)
	{
		argv[i]=NULL;
	}
	
	if((len=write(1,tip,11))<0)
	{
		perror("write error!");
		exit(0);
	}

	if((len=read(0,buffer,sizeof(buffer)))<0)
	{
		perror("read error!");
		exit(0);
	}
	i=0;
	j=0;
        k=0;
        while(i<len-1)
	{
		
	        while((buffer[i]!=' '&&buffer[i]!='\n')&&i<len-1)
	        {
	         	cmd[j][k]=buffer[i];
	        	i++;
			k++;
         	}
		cmd[j][k]='\0';
        	argv[j]=cmd[j];
		if(buffer[i]==' ')
		{
			while(buffer[i]==' ')
				i++;
			k=0;
			j++;
			
		}
	}
         
	while((pid=fork())<0);
	if(pid==0)
	{
		file=cmd[0];
	       	tag=execvp(file,argv);
		if(tag<0)
			printf("Bad command!\n");
	}
	else{
		wait(0);
		goto again;
	}
	
	return 0;
}