BASH - GREP - invert很多不起作用

Question

我正在尝试通过用户"apache“查找一些打开的文件描述符。我想排除ls: /proc/PID/fd: No such file or directory，但GREP排除不起作用：

# for pid in $(lsof -u apache | awk '{ print $2 }' | uniq); do ls -1 /proc/$pid/fd | grep -v "No"; done | wc -l 
ls: /proc/PID/fd: No such file or directory
1944

Answer 1

试试|& grep -v "No such file or directory"

与|不同，|&还将重定向ls的错误输出

Answer 2

尝试：

for pid in $(lsof -u apache | tail -n +2 | awk '{ print $2 }' | uniq); do ls -1 /proc/$pid/fd ; done | wc -l