我安装gnome-shell-extensions（已经安装）：
┌jack@comp:~
└sudo apt install gnome-shell-extensions
Reading package lists... Done
Building dependency tree
Reading state information... Done
gnome-shell-extensions is already the newest version (3.28.0-2).
The following packages were automatically installed and are no longer required:
calligra-data calligra-libs calligrasheets calligrastage calligrastage-data calligrawords calligrawords-data fluidr3mono-gm-soundfont fonts-dejavu freepats gstreamer1.0-doc gstreamer1.0-qt5 karbon libbsh-java libde265-0
libel-api-java libfluidsynth1 libgssdp-1.0-3 libgstreamer1.0-dev libgupnp-1.0-4 libgupnp-igd-1.0-4 libhsqldb1.8.0-java libjsp-api-java libkchart2 libkchart2-l10n libkf5kdelibs4support-data libkf5kdelibs4support5
libkf5kdelibs4support5-bin libkf5khtml-bin libkf5khtml-data libkf5khtml5 libllvm7 libmjpegutils-2.1-0 libmms0 libmodplug1 libmpeg2encpp-2.1-0 libmplex2-2.1-0 libnice10 libofa0 libreoffice-avmedia-backend-gstreamer
libsdl2-mixer-2.0-0 libservlet-api-java libservlet3.1-java libspandsp2 libspnav0 libsrtp2-1 libvo-aacenc0 libwebsocket-api-java libwildmidi-config libwildmidi2 libwxgtk3.0-gtk3-0v5 libzbar0 linux-headers-4.15.0-76
linux-headers-4.15.0-76-generic linux-image-4.15.0-76-generic linux-modules-4.15.0-76-generic linux-modules-extra-4.15.0-76-generic okular-backend-odp okular-backend-odt python-wxgtk3.0 python-wxversion
Use 'sudo apt autoremove' to remove them.
0 to upgrade, 0 to newly install, 0 to remove and 373 not to upgrade.\
我跑：
┌jack@comp:~
└gnome-extensions
gnome-extensions: command not found
知道哪里出了问题吗？