Fixing ‘sudo: apt-get: command not found’ in Terminal

aptcommand linegnome-terminalinterface

Lately some really bad things have been happening with my computer, having to do with lack of icons and all kinds of bad things going with my graphical interface. All the bad things in the appeal are accompanied by a certain disability of my terminal. I'm using 12.04 with Gnome Classic view with no effects.

Let's have a sudo apt-get update.

I get sudo: apt-get: command not found message. And it is the way it goes with all my apt-get commands.

What can it mean? How to fix this, especially concerning all the other problems I'm experiencing?

Best Answer

The short answer:

Re-install Ubuntu from a Live CD or USB.

The long version:

The long version would be a waste of your time: your system will never be clean, but if you insist you could try:

copying everything (missing) except for the /home folder from the Live CD/USB to your HDD.

do a re-install/repair over the broken system again with the Live CD / USB stick.

download the deb file for apt-get and install as explained on above posts.

I would definitely go for a fresh new install as there are so many things to do and so little time.

Related Solutions

Ubuntu – How to rollback an apt-get upgrade from command line

You can display packages that are going to be upgraded and version changes with:

sudo apt-get update
sudo apt-get -V upgrade

The '-V' flag shows you the additional info. As for the snapshots - you really have to roll your own here.

My favourite method for having the rollback ability is using LVM with snapshots on Linux - but the last time I checked, there was no progress on the automated rollback to the chosen snapshot. This might have changed since then (I'd be happy for someone to correct me), but you can always boot using root=/dev/vg0/root-snap kernel parameter (for instance) and then use rsync to sync the snapshot /dev/vg0/root-snap to the original volume /dev/vg0/root and then discard the snapshot. Not ideal but can be automated.

Of course ZFS snapshots rock but there's no official, production-ready ZFS support for Linux (yes, I'm aware of zfsonlinux.org and ZFS-FUSE), so unless you're just playing around, that's not really a feasible option for you.

UPDATE: it looks that we can now rollback (merge in LVM2 parlance) snapshots. So the update would take the following form with LVM2:

Create a 5GB snapshot of your root LV:

lvcreate -s /dev/vg0/root -L5G -n root-snap
Update the package (as above).
Roll back if necessary by running:

lvconvert --merge /dev/vg0/root-snap

And because /dev/vg0/root (the original LV) is opened, lvconvert will notify you that the /dev/vg0/root will be rolled back to /dev/vg0/root-snap upon the next activation of this volume. This happens when you run

lvchange -ay /dev/vg0/root

while this LV is closed, which is upon the next boot or after running:

lvchange -an /dev/vg0/root

Consequences of Using Apt-Get in Ubuntu Touch

No (but it will feel like yes for a while)

If you enable rw on / and start modifying it, nothing disables the delivery of OTA updates. So when they arrive, they will be offered to you for install, as before.

However, the OTA process does a very simple thing to the filesystem. It just untars a large set of files on top of the filesystem you have. Since it knows (because it should be ro) the previous filesystem, this is simply a set of the files that have changed.

So you are gambling. Do the changes you have made cause side effects when this happens? In general, yes. In general, you will have modified some file in the / filesystem, and added software that depends on that change. When an OTA is installed, that change will be removed, and potentially replaced with a conflicting change. At this point, what happens next is unknowable, and certainly untested.

So, in practice, some apt-get installs will largely add software in parallel to the existing files, so will not be much impacted by an OTA. However, one file set will certainly be impacted - apt's own record keeping (OTA's deliver the records used in construction of the ro filesystem). So your system will lose the knowledge of what is there, and what is not.

This is the core danger with apt-get upgrade. It will always be performed with an incorrect database of what is on the device, so it cannot be guaranteed to succeed. As your additions become more complex, and as the underlying system makes major transitions (such as when the phones moved from Utopic to Vivid), apt-get run by hand will do the wrong thing.

Every OTA then becomes a gamble, until you perform a wipe & reinstall.

Your system will become slowly broken - see above.