The system does not start. Did it by using
rm - R accidentally. How can I recover the system?
You need to reinstall all applications which have files in
Boot system from Recovery Mode with root prompt.
Remount rootfs to read-write mode with
mount -o rw,remount /.
Raise up ethernet interface and get IP address from DHCP server:
dhclient enp0s3(check correct interface name in
Specify DNS server by
rm /etc/resolv.conf echo "nameserver 192.168.1.1" > /etc/resolv.conf
192.168.1.1to yours gateway/router)
You need to fix the
dpkgpackage as it misses the
/usr/share/dpkg/cputablefile (otherwise you will face the
"E: error reading the cpu table"on any apt/apt-get command)
wget http://mirrors.kernel.org/ubuntu/pool/main/d/dpkg/dpkg_126.96.36.199ubuntu2.1_amd64.deb dpkg -i dpkg_188.8.131.52ubuntu2.1_amd64.deb
or installing it from cache:
dpkg -i /var/cache/apt/archives/dpkg_*.deb
update package cache:
reinstall essential componenets
apt-get install --reinstall debconf linux-base mkdir /usr/share/python apt-get install --reinstall python2.7-minimal python3-minimal
and then use one-liner below:
apt-get install --reinstall $(dpkg -S /usr/share/ | sed 's/,//g' | sed 's/: \/usr\/share//g')
dpkg -S /usr/share/shows the list of comma-separated packages
sed 's/,//g'- removes commas
sed 's/: \/usr\/share//g'- removes
: /usr/sharein the end
This part may fail with messages about some packages. For example on my VM I have had a problem with
bsdmainutils, so I reinstalled them with:
dpkg -i /var/cache/apt/archives/bsdmainutils_*.deb
and then reran one-liner above.
fix broken packages
dpkg --configure -a apt-get install -f
rm /etc/resolv.conf ln -s /run/systemd/resolve/stub-resolv.conf /etc/resolv.conf
Note: the resulting fixed system do not show any problems while running
sudo apt-get check or
sudo debsums --all --changed.
Short answer: you can't and you have to reinstall the apps, as suggested by a previous answer.
However, before that, I would mount the drive in another computer and test undelete utilities which are available for ext3/ext4. A quick search in Google points to these ones: