Solving "-bash: cannot create temp file for here-document: No space left on device"

Today in this post, I am going to describe about a problem I faced while I was trying to update WowzaStreamingEngine in Ubuntu.  While I ran the script for the update I came to this problem that stated:

-bash: cannot create temp file for here-document: No space left on device

When I checked for diskspace using the command:

df -h

I had the following output:

/dev/root        20G  3.1G   16G  17% /
devtmpfs         16G  4.0K   16G   1% /dev
none            4.0K     0  4.0K   0% /sys/fs/cgroup
none            3.2G  848K  3.2G   1% /run
none            5.0M     0  5.0M   0% /run/lock
none             16G     0   16G   0% /run/shm
onne            100M     0  100M   0% /run/user
/dev/md3        1.8T   77G  1.7T   5% /home
overflow        1.0M  1.0M     0 100% /tmp

I could clearly see there was enough space. But if you look the above clearly again you will see that /tmp is using 100% usage. This was the cause for the above error message. Now I had to get rid of it. So, the solution was to unmount it. I tried to unmount but again I got another error message saying the device is busy. To find out what process was using the device I ran the following command:

lsof | grep /tmp

This shows the process that kept the device busy. Killing the process and unmounting the device worked. You can also do lazy unmount using the command

umount -l /tmp

or

umount -l overflow

After that I was able to continue the update.