install *.dmg from command line in OSX

Installing

STEP 1: mount the apple disk image file as /Volumes

hdiutil mount ideaIC-15.0.2-custom-jdk-bundled.dmg 
----
----
/dev/disk2          GUID_partition_scheme          
/dev/disk2s1        Apple_HFS                      /Volumes/IntelliJ IDEA 15 CE

STEP 2: copy the mounted *.app to /Apps

sudo cp -r "/Volumes/IntelliJ IDEA 15 CE/IntelliJ IDEA 15 CE.app" /Applications

If the mounted file is *.pkg instead of *.app, then 

$ sudo installer -pkg /Applications/chefdk-1.0.3-1.pkg -target /
installer: Package name is Chef Development Kit
installer: Upgrading at base path /
installer: The upgrade was successful.

STEP 3: unmount the file from /Volumes

hdiutil unmount "/Volumes/IntelliJ IDEA 15 CE"
"/Volumes/IntelliJ IDEA 15 CE" unmounted successfully.

OR

sudo cp -r ggts-bundle/ggts-3.6.4.RELEASE/GGTS.app/ /Applications/

Uninstalling

remove from /Apps

$ ll /Applications/IntelliJ\ IDEA*
/Applications/IntelliJ IDEA CE.app:
total 0
drwxr-xr-x@ 12 prayagupd  admin  408 Jan 21 00:33 Contents

/Applications/IntelliJ IDEA.app:
total 0
drwxr-xr-x@ 13 prayagupd  admin  442 Dec 25 09:21 Contents

rm -rf /Applications/IntelliJ\ IDEA\ CE.app/