Ubuntu-delete unnecessary kernel versions

First, the list of installed kernel versions is displayed.

Dpkg -- Get-selections | grep Linux

 

Shown as follows:
Libselinux1 install
Linux-firmware install
Linux-generic install
Linux-generic-PAE install
Install linux-headers-2.6.31-15
Install linux-headers-2.6.31-15-generic
Install linux-headers-2.6.31-15-generic-pae
Install linux-headers-2.6.31-16
Install linux-headers-2.6.31-16-generic
Install linux-headers-2.6.31-16-generic-pae
Linux-headers-generic install
Linux-headers-generic-PAE install
Linux-headers-server install
Install linux-image-2.6.31-14-generic
Install linux-image-2.6.31-14-generic-pae
Install linux-image-2.6.31-15-generic
Install linux-image-2.6.31-15-generic-pae
Install linux-image-2.6.31-16-generic
Install linux-image-2.6.31-16-generic-pae
Linux-image-generic install
Linux-image-generic-PAE install
Linux-image-server install
Linux-libc-dev install
Linux-server install
Linux-sound-base install
Syslinux install
Util-Linux install

 

Then I want to unload the old version.2.6.31-15


Sudo apt-Get remove linux-headers-2.6.31-15

The result is as follows:

Reading the package list... complete
Analyzing the dependency tree of the software package
Reading status information... complete
The following software packages are automatically installed and are no longer in use:
Libclucene0ldbl libqt4-opengl libxine1-x kdebase-runtime-data-common kdebase-runtime libqt4-sql-mysql libqt4-dbus libxine1-misc-plugins kdelibs5 libxcb-xv0 libqt4-qt3support
Libknotifitem1 Python-chm kde-icons-oxygen libxine1-bin libexiv2-5 kdebase-runtime-bin-kde4 liblzma0 libsoprano4 libqt4-webkit kdelibs5-data libxcb-shape0 libqt4-sql
Libqt4-svg libstreamanalyzer0 libqt4-xml libplasma3 phonon-backend-xine libqt4-designer kdelibs-bin libqt4-phonon khelpcenter4 libstreams0 exiv2 libqt4-script libxcb-shm0
Soprano-daemon kdebase-runtime-data libxine1-console libxine1
Use 'apt-Get autoremove 'to delete them.
The following software packages will be [uninstalled ]:
Linux-headers-2.6.31-15 linux-headers-2.6.31-15-generic linux-headers-2.6.31-15-generic-pae
A total of 0 software packages have been upgraded, 0 software packages have been installed, 3 software packages have to be uninstalled, and 0 software have not been upgraded.
After decompression, 90.8 MB of space will be empty.
Do you want to continue? [Y/n] y
(Reading the database... the system currently has a total of 175128 files and directories installed .)
Deleting linux-headers-2.6.31-15-generic-pae...
Deleting linux-headers-2.6.31-15-generic...
Deleting linux-headers-2.6.31-15...