Failed to write (No space left on device) [duplicate]

I am working on an Ubuntu virtualbox and trying to install curl using sudo apt-get install curl -y.

I got a response saying there were unmet dependencies and saying You might want to run 'apt-get -f install' to correct these:

So, I execute apt-get -f install and encounter a new problem:

After this operation, 43.0 MB of additional disk space will be used.
(Reading database ... 273817 files and directories currently installed.)
Preparing to unpack .../linux-image-3.13.0-91-generic_3.13.0-91.138_amd64.deb ...
Done.
Unpacking linux-image-3.13.0-91-generic (3.13.0-91.138) ...
dpkg: error processing archive /var/cache/apt/archives/linux-image-3.13.0-91-generic_3.13.0-91.138_amd64.deb (--unpack):
 cannot copy extracted data for './boot/vmlinuz-3.13.0-91-generic' to '/boot/vmlinuz-3.13.0-91-generic.dpkg-new': failed to write (No space left on device)
No apport report written because the error message indicates a disk full error
                                                                              dpkg-deb: error: subprocess paste was killed by signal (Broken pipe)
Examining /etc/kernel/postrm.d .
run-parts: executing /etc/kernel/postrm.d/initramfs-tools 3.13.0-91-generic /boot/vmlinuz-3.13.0-91-generic
run-parts: executing /etc/kernel/postrm.d/zz-update-grub 3.13.0-91-generic /boot/vmlinuz-3.13.0-91-generic
Errors were encountered while processing:
 /var/cache/apt/archives/linux-image-3.13.0-91-generic_3.13.0-91.138_amd64.deb
E: Sub-process /usr/bin/dpkg returned an error code (1)

Basically, it's complaining there is no space left on device. df -h confirms:

Filesystem                Size  Used Avail Use% Mounted on
/dev/mapper/ITS--vg-root   38G   18G   18G  51% /
none                       4.0K     0  4.0K   0% /sys/fs/cgroup
udev                       988M   12K  988M   1% /dev
tmpfs                      201M  540K  200M   1% /run
none                       5.0M     0  5.0M   0% /run/lock
none                       1001M  4.0K 1001M   1% /run/shm
none                       100M     0  100M   0% /run/user
/dev/sda1                  236M  226M     0 100% /boot

So if I'm reading this correctly, apt-get -f install is trying to write 43.0 MB worth of content into available space of 18G.

Why is it complaining there is inadequate space?


Your problem isn't the 18GB free on /

The problem is:

/dev/sda1                  236M  226M     0 100% /boot

The package installer is working on /boot/vmlinuz-3.13.0-91-generic and there is no space available.

You need to increase the size of this partition.

As Anwar stated in comment a minute ago see: askubuntu.how-do-i-increase-the-size-of-boot

Originally I said to see the Q&A: askubuntu.com ..how-to-increase-size-of-boot-partition-using-gparted which is also helpful.