$ sudo apt-get remove libdmalloc5 

Uninstall libdmalloc5 including dependent package

If you would like to remove libdmalloc5 and it's dependent packages which are no longer needed from Ubuntu,

$ sudo apt-get remove --auto-remove libdmalloc5 

Use Purging libdmalloc5

If you use with purge options to libdmalloc5 package all the configuration and dependent packages will be removed.

$ sudo apt-get purge libdmalloc5 

If you use purge options along with auto remove, will be removed everything regarding the package, It's really useful when you want to reinstall again.

$ sudo apt-get purge --auto-remove libdmalloc5 

See Also,