如果我运行下面的命令，只有out1输出，out2和out3为空。
# this is just to generate a self-signed certificate
openssl genrsa -out /tmp/ssl.key 2048
openssl req -sha256 -new -key /tmp/ssl.key -out /tmp/ssl.csr -subj /CN=localhost
openssl x509 -req -days 365 -in /tmp/ssl.csr -signkey /tmp/ssl.key -out /tmp/ssl.crt
# works
openssl s_server -cert /tmp/ssl.crt -key /tmp/ssl.key -accept 444 > out1
# does not work, but if I run without '> out2' it works
openssl s_server -cert /tmp/ssl.crt -key /tmp/ssl.key -accept 446 | sed "s/ACCEPT/ACCEPT445/g" > out2 …