Eu digitei isso no terminal:
sudo apt-get remove python3
E isso me deu a seguinte saída:
Reading package lists... Done
Building dependency tree
Reading state information... Done
The following packages were automatically installed and are no longer required:
fonts-dejavu-extra gir1.2-secret-1 icedtea-netx-common libbonobo2-0
libbonobo2-common libcpufreq0 libgconf2-4 libgif4 libgnome2-0 libgnome2-bin
libgnome2-common libgnomevfs2-0 libgnomevfs2-common libidl-common libidl0
liborbit2 tzdata-java
Use 'apt-get autoremove' to remove them.
The following packages will be REMOVED:
apparmor apport apport-gtk aptdaemon apturl apturl-common bluez bluez-alsa
bluez-gstreamer checkbox checkbox-qt command-not-found
deja-dup-backend-ubuntuone dh-python firefox flashplugin-installer
foomatic-db-compressed-ppds friends friends-dispatcher friends-facebook
friends-twitter gedit gnome-bluetooth gnome-control-center
gnome-control-center-datetime gnome-control-center-signon
gnome-control-center-unity gnome-menus gnome-orca gnome-user-share
indicator-bluetooth indicator-cpufreq language-selector-common
language-selector-gnome libfriends0 lightdm-remote-session-uccsconfigure
lsb-release nautilus-share onboard onboard-data oneconf openprinting-ppds
printer-driver-foo2zjs printer-driver-postscript-hp printer-driver-ptouch
printer-driver-pxljr python-commandnotfound python-ubuntuone-client
python-ubuntuone-control-panel python3 python3-apport python3-apt
python3-aptdaemon python3-aptdaemon.gtk3widgets python3-aptdaemon.pkcompat
python3-brlapi python3-cairo python3-chardet python3-commandnotfound
python3-crypto python3-dbus python3-debian python3-defer python3-dirspec
python3-distupgrade python3-feedparser python3-gdbm python3-gi
python3-gi-cairo python3-httplib2 python3-louis python3-lxml python3-mako
python3-markupsafe python3-oauthlib python3-oneconf
python3-piston-mini-client python3-pkg-resources python3-problem-report
python3-pyatspi python3-six python3-software-properties python3-speechd
python3-uno python3-update-manager python3-xdg python3-xkit rhythmbox
rhythmbox-mozilla rhythmbox-plugin-cdrecorder rhythmbox-plugin-magnatune
rhythmbox-plugin-zeitgeist rhythmbox-plugins rhythmbox-ubuntuone
sessioninstaller software-center software-center-aptdaemon-plugins
software-properties-common software-properties-gtk
system-config-printer-gnome thin-client-config-agent
ttf-mscorefonts-installer ubuntu-desktop ubuntu-drivers-common
ubuntu-minimal ubuntu-release-upgrader-core ubuntu-release-upgrader-gtk
ubuntu-standard ubuntuone-client ubuntuone-control-panel
ubuntuone-control-panel-qt ufw unattended-upgrades unity-lens-friends
unity-lens-photos unity-scope-audacious unity-scope-calculator
unity-scope-chromiumbookmarks unity-scope-clementine
unity-scope-colourlovers unity-scope-devhelp unity-scope-firefoxbookmarks
unity-scope-gdrive unity-scope-gmusicbrowser unity-scope-gourmet
unity-scope-guayadeque unity-scope-home unity-scope-manpages
unity-scope-musique unity-scope-openclipart unity-scope-texdoc
unity-scope-tomboy unity-scope-virtualbox unity-scope-yelp
unity-scope-zotero unity-tweak-tool update-manager update-manager-core
update-notifier update-notifier-common usb-creator-common usb-creator-gtk
webaccounts-extension-common xdiagnose xul-ext-ubufox xul-ext-unity
xul-ext-webaccounts
0 upgraded, 0 newly installed, 147 to remove and 1 not upgraded.
After this operation, 162 MB disk space will be freed.
Do you want to continue [Y/n]? n
Por que me pede para desinstalar todas as outras coisas? Problemas de um noob Linux: /
O problema é com o que é chamado de dependências.
Esses aplicativos dependem do " python3 " que está sendo instalado para funcionar corretamente.
Você ainda pode instalar qualquer outra versão do python que quiser, mas precisará chamá-la especificamente na linha de comando.