64位linux ps命令执行问题

[奕诚]

如题，在64linux 终端 下 输入如下命令：
ps -ef | grep ora_ |grep XXX|wc -l
输出为0
但是在linux C程序下用 popen 执行，输出为1；
请问各位linux大神，为什么执行同样的命令，在终端下和程序下执行结果不一样呢？
PS:如果在终端下执行ps -ef | grep ora_ |grep XXX|wc -l 结果大于0的话 在程序里popen 执行输出的结果一样。

[羽飞]

把popen去掉wc -l看看结果是啥

[大熊猫侯佩]

你将返回0的命令串拆开，从头开始一段一段检查

[小笨和漂向北方]

that's because you pass -ef to ps, which will list all processes on the system, including the one created popen, it loos like sh -c ps -ef | grep ora_ |grep XXX|wc -l so the correct line count should be whatever you read from pipe minus 1

[小笨和漂向北方]

oops, I meant "including the one created by popen" The popen() function opens a process by creating a pipe, forking, and invoking the shell.

[nswcfd]

是不是执行popen的程序本身，也匹配上XXX了？

[奕诚]

3楼正解。可惜不能结贴给分了，十分抱歉，感谢楼上各位的热心解答！