观察linux管道现象

第一个进程

[root@LinuxOparation newDir]# echo $$
32479
[root@LinuxOparation newDir]# { echo $BASHPID ; read x;  } | { cat ; echo $BASHPID; read y; }
407

第二个进程

[root@LinuxOparation fd]# ps -ef | grep 32479
root       407 32479  0 03:25 pts/0    00:00:00 -bash
root       408 32479  0 03:25 pts/0    00:00:00 -bash
root       412   381  0 03:25 pts/1    00:00:00 grep --color=auto 32479
root     32479 32477  0 01:28 pts/0    00:00:00 -bash
[root@LinuxOparation fd]# cd /proc/407/fd
[root@LinuxOparation fd]# ll
total 0
lrwx------ 1 root root 64 Jul 20 03:25 0 -> /dev/pts/0
l-wx------ 1 root root 64 Jul 20 03:25 1 -> pipe:[2219234]
lrwx------ 1 root root 64 Jul 20 03:25 2 -> /dev/pts/0
lrwx------ 1 root root 64 Jul 20 03:25 255 -> /dev/pts/0
lr-x------ 1 root root 64 Jul 20 03:25 6 -> /root/newDir/newfile.txt
[root@LinuxOparation fd]# cd /proc/408/fd
[root@LinuxOparation fd]# ll
total 0
lr-x------ 1 root root 64 Jul 20 03:25 0 -> pipe:[2219234]
lrwx------ 1 root root 64 Jul 20 03:25 1 -> /dev/pts/0
lrwx------ 1 root root 64 Jul 20 03:25 2 -> /dev/pts/0
lrwx------ 1 root root 64 Jul 20 03:25 255 -> /dev/pts/0
lr-x------ 1 root root 64 Jul 20 03:25 6 -> /root/newDir/newfile.txt

也可以使用lsof -op pid命令来查看，如下图：

image.png