利用管道PIPE实现命令执行结果的动态显示

该程序用来执行由命令行传递的命令,并动态显示! 不对之处请各位大侠多多指教！！
例如运行如下:
./my_system ping 127.0.0.1 [回车]
PING 127.0.0.1 (127.0.0.1) 56(84) bytes of data.
64 bytes from 127.0.0.1: icmp_seq=1 ttl=64 time=0.078 ms

64 bytes from 127.0.0.1: icmp_seq=2 ttl=64 time=0.053 ms

64 bytes from 127.0.0.1: icmp_seq=3 ttl=64 time=0.052 ms

64 bytes from 127.0.0.1: icmp_seq=4 ttl=64 time=0.051 ms

64 bytes from 127.0.0.1: icmp_seq=5 ttl=64 time=0.052 ms

64 bytes from 127.0.0.1: icmp_seq=6 ttl=64 time=0.051 ms

........

//////////////////////////////////////////////////////////////////////
#include <stdio.h>
#include <unistd.h>
#include <string.h>

static int my_system(const char* pCmd, char* pResult, int size)
{
int fd[2];
int pid;
int count;
int left;
char* p = 0;
int maxlen = size - 1;

memset(pResult, 0, size);//

if(pipe(fd))//
{
printf("pipe error\n");
return -1;
}

if( (pid = fork()) == 0 )//
{// chile process
close( 1 );
dup2( fd[1],1 );//
close( fd[1] );
close( fd[0] );
system( pCmd );//
exit( 0 );
}

// parent process
close( fd[1] );
p = pResult;
left = maxlen;
while( ( count = read( fd[0], p, left ) ) )//
{
pResult = p;
p += count;
left -= count;
if( left == 0 )
break;
printf( "%s\n", pResult );
}
close( fd[0] );
return 0;
}

int main( int argc, char *argv[] )
{
int i = 1;
char spac[] = " ";
char pCmd[1025];

if( argc < 2 )
{
printf( "Syntax error...\n" );
return 255;
}

memset(pCmd, 0, strlen(pCmd) );//
for( ; i < argc; i++ )
{
strcat( pCmd, argv[i] );//
strcat( pCmd, spac );//
}
char result[1024];
my_system( pCmd, result, 1024 );//
printf( "\n%s\n", result );
return 0;
}

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