我正在尝试在 Ubuntu 18.04 LTS 上安装 vsftpd，但是运行时apt-get install vsftpd出现此错误：
You might want to run 'apt --fix-broken install' to correct these.
The following packages have unmet dependencies:
linux-image-generic : Depends: linux-image-4.15.0-42-generic but it is not going to be installed
Recommends: thermald but it is not going to be installed
linux-modules-extra-4.15.0-39-generic : Depends: linux-image-4.15.0-39-generic but it is not going to be installed or
linux-image-unsigned-4.15.0-39-generic but it is not going to be installed
linux-modules-extra-4.15.0-42-generic : Depends: linux-image-4.15.0-42-generic but it is not going to be installed or
linux-image-unsigned-4.15.0-42-generic but it is not going to be installed
E: Unmet dependencies. Try 'apt --fix-broken install' with no packages (or specify a solution).
我尝试运行apt --fix-broken install，apt-get install -f vsftpd但没有成功。
我查看了这些答案，但解决方案对我没有用： 无法安装新软件/软件包 无法安装新软件：依赖性问题
更新：
df -h输出：
Filesystem Size Used Avail Use% Mounted on
/dev/root 39G 7.3G 30G 21% /
devtmpfs 989M 0 989M 0% /dev
tmpfs 992M 0 992M 0% /dev/shm
tmpfs 992M 680K 992M 1% /run
tmpfs 5.0M 0 5.0M 0% /run/lock
tmpfs 992M 0 992M 0% /sys/fs/cgroup
/dev/xvda1 232M 224M 0 100% /boot
tmpfs 199M 0 199M 0% /run/user/0
df -i输出：
Filesystem Inodes IUsed IFree IUse% Mounted on
/dev/root 2537760 337826 2199934 14% /
devtmpfs 253100 434 252666 1% /dev
tmpfs 253889 1 253888 1% /dev/shm
tmpfs 253889 606 253283 1% /run
tmpfs 253889 4 253885 1% /run/lock
tmpfs 253889 18 253871 1% /sys/fs/cgroup
/dev/xvda1 62248 326 61922 1% /boot
tmpfs 253889 10 253879 1% /run/user/0
apt-cache policy linux-image-generic输出：
linux-image-generic:
Installed: 4.15.0.42.44
Candidate: 4.15.0.42.44
Version table:
*** 4.15.0.42.44 500
500 http://us.archive.ubuntu.com/ubuntu bionic-updates/main amd64 Packages
500 http://security.ubuntu.com/ubuntu bionic-security/main amd64 Packages
100 /var/lib/dpkg/status
4.15.0.20.23 500
500 http://us.archive.ubuntu.com/ubuntu bionic/main amd64 Packages
4.4.0.139.145 500
500 http://security.ubuntu.com/ubuntu xenial-security/main amd64 Packages
uname -r输出：
4.15.0-36-generic
更新 2： 我尝试这个命令：
dpkg -l linux-image-\* | grep ^ii
它仅显示一个内核：
ii linux-image-4.15.0-36-generic 4.15.0-36.39 amd64 Signed kernel image generic
当我尝试删除时：
apt-get remove linux-image-4.15.0-36-generic
返回的是：
ou might want to run 'apt --fix-broken install' to correct these.
The following packages have unmet dependencies:
linux-image-generic : Depends: linux-image-4.15.0-42-generic but it is not going to be installed
Recommends: thermald but it is not going to be installed
linux-modules-extra-4.15.0-36-generic : Depends: linux-image-4.15.0-36-generic but it is not going to be installed or
linux-image-unsigned-4.15.0-36-generic but it is not going to be installed
linux-modules-extra-4.15.0-39-generic : Depends: linux-image-4.15.0-39-generic but it is not going to be installed or
linux-image-unsigned-4.15.0-39-generic but it is not going to be installed
linux-modules-extra-4.15.0-42-generic : Depends: linux-image-4.15.0-42-generic but it is not going to be installed or
linux-image-unsigned-4.15.0-42-generic but it is not going to be installed
E: Unmet dependencies. Try 'apt --fix-broken install' with no packages (or specify a solution).