why htpasswd from apache2-utils output redirect failed

Question

while I'm trying to redirect htpasswd's out and input to a pipe file, the prompt messages always print without redirection. I tried manny method, all failed. anyone help?

mkfifo pipe

1. htpasswd -m aaa test &> pipe
2. htpasswd -m aaa test 2>&1 >pipe
3. htpasswd -m aaa test 2>pipe

always prompt print for-ground. Any advise is welcome :)

Answer 1

Just close this question, for I use a purl shell script. htpasswd can be used as silence mode: htpasswd -b that all.