sudo vim /etc/apt/mirror.list
############# config ##################
#
set base_path /var/spool/apt-mirror
set mirror_path $base_path/mirror
set skel_path $base_path/skel
set var_path $base_path/var
set cleanscript $var_path/clean.sh
# set defaultarch <running host architecture>
# set postmirror_script $var_path/postmirror.sh
# set run_postmirror 0
set nthreads 20
set _tilde 0
#
############# end config ##############
# mirror additional architectures
#deb-alpha http://ftp.us.debian.org/debian unstable main contrib non-free
deb-amd64 http://ftp.us.debian.org/debian unstable main contrib non-free
#deb-armel http://ftp.us.debian.org/debian unstable main contrib non-free
#deb-hppa http://ftp.us.debian.org/debian unstable main contrib non-free
deb-i386 http://ftp.us.debian.org/debian unstable main contrib non-free
#deb-ia64 http://ftp.us.debian.org/debian unstable main contrib non-free
#deb-m68k http://ftp.us.debian.org/debian unstable main contrib non-free
#deb-mips http://ftp.us.debian.org/debian unstable main contrib non-free
#deb-mipsel http://ftp.us.debian.org/debian unstable main contrib non-free
#deb-powerpc http://ftp.us.debian.org/debian unstable main contrib non-free
#deb-s390 http://ftp.us.debian.org/debian unstable main contrib non-free
#deb-sparc http://ftp.us.debian.org/debian unstable main contrib non-free
clean http://ftp.us.debian.org/debian
执行apt-mirror。
由于apt-mirror可能有bug，所以可能需要手动下载icon64x64@2.tar.gz文件。
cd <apt-mirror-home>/mirror/archive.ubuntu.com/ubuntu/dists
for dist in bionic bionic-updates bionic-security; do
for comp in main multiverse universe; do
for size in 48 64 128; do
wget http://archive.ubuntu.com/ubuntu/dists/${dist}/${comp}/dep11/icons-${size}x${size}@2.tar.gz -O ${dist}/${comp}/dep11/icons-${size}x${size}@2.tar.gz;
done
done
done
本文为摘抄，没有修改，请根据实际源位置进行修改。
参考：
https://www.cnblogs.com/pengdonglin137/p/3474260.html
https://github.com/apt-mirror/apt-mirror/issues/102