debian9 ps 命令不能用

# cat > /etc/apt/sources.list << EOF
> deb http://mirrors.aliyun.com/debian/ stretch main non-free contrib
deb-src http://mirrors.aliyun.com/debian/ stretch main non-free contrib
deb http://mirrors.aliyun.com/debian-security stretch/updates main
deb-src http://mirrors.aliyun.com/debian-security> > > stretch/updates main
deb http://mirrors.aliyun.com/debian/ stretch-updates main non-free contrib
deb-src http://mirrors.aliyun.com/debian/ stretch-updates main non-free contrib
deb http://mirrors.aliyun.com/debian/ stretch-backports main non-free contrib
deb-src http://mirrors.aliyun.com/debian/ stretch-backports main non-free contrib
> EOF

apt-get update && apt-get install procps

=====================================
debian11 

echo "deb https://mirrors.aliyun.com/debian/ bullseye main non-free contrib"  >/etc/apt/sources.list
echo "deb-src https://mirrors.aliyun.com/debian/ bullseye main non-free contrib" >>/etc/apt/sources.list
echo "deb https://mirrors.aliyun.com/debian-security/ bullseye-security main" >>/etc/apt/sources.list
echo "deb-src https://mirrors.aliyun.com/debian-security/ bullseye-security main" >>/etc/apt/sources.list
echo "deb https://mirrors.aliyun.com/debian/ bullseye-updates main non-free contrib" >>/etc/apt/sources.list
echo "deb-src https://mirrors.aliyun.com/debian/ bullseye-updates main non-free contrib" >>/etc/apt/sources.list
echo "deb https://mirrors.aliyun.com/debian/ bullseye-backports main non-free contrib" >>/etc/apt/sources.list
echo "deb-src https://mirrors.aliyun.com/debian/ bullseye-backports main non-free contrib" >>/etc/apt/sources.list

最后需要：
apt-get update -y