I'm a bit new to linux and ubuntu specially command line stuff. So I currently have a VPS which was running on a 14.04 ubuntu LTS, and as I needed a 16.04 version, I searched and found the way to upgrade it. I SSHed into the server and started upgrading, everything went well and it asked for a restart and I let it. After that I'm not able to to ssh into it. I had a KVM thingy with a VNC to connect and see what is going on. I don't know if an ubuntu server should boot on default (log in a user) or not, but it wasn't booting and there was a message :  /dev/vda1: clean, xxxx/xxxx files, xxxx/xxxx blocks   so I went to manually login using ctrl + alt + f2 and it is upgraded to 16.04 and the SSH service is running with no problem, but I noticed I couldn't do apt-get update or anything similar because I have no internet connection and after 24 hours searching I've come here asking for help.  I don't if it may help but these are the results of the commands I've ran  sudo lshw -C network gives:   and systemctl status networking.service gives :
I'm trying to configure a ubuntu server network. [Edit] My ifconfig: lo: flags=73&lt;UP,LOOPBACK,RUNNING&gt; mtu 65536 inet 127.0.0.1 netmask 255.0.0.0 inet6 ::1 prefixlen 128 scopeid 0x10&lt;host&gt; loop txqueuelen 1000 (Loopback Local) RX packets 352 bytes 26160 (26.1KB) RX erors 0 dropped 0 overruns 0 frame 0 TX packets 352 bytes 26160 (26.1KB) TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0  I edited the /etc/network/interfaces file and here is how it is: auto lo auto eth0 iface eth0 inet static address 192.168.15.141 netmask 255.255.255.0 gateway 192.168.15.1  I'm trying to restart the server and I'm using: sudo ifdown --exclude=lo -a &amp;&amp; sudo ifup --exclude=lo -a  This command is an answer from this link:  And I'm getting the following error: Cannot find device &quot;eth0&quot; Failed to bring up eth0.  I'm pretty lay in configuring a server, so I have no idea what's going on. Can someone help me please?
What kind of passport do I need when entering the USA? I heard that you need a biometric passport if you want to enter USA. However, my friend has a biometric passport, but no fingerprints in it. Is this enough? And how long has the passport to be valid? Is it okay if it expires on the day after his return date? How do I add myself back as a sudo user? I clean-installed Ubuntu 11.10 today, and then installed VirtualBox.  This required me to add myself to the vboxusers group, and since 11.10 seems to no longer have a graphical app to add users to a group, I ran the following command:  sudo usermod -G vboxusers stephane   This is a problem.  I now see what I should have run instead is:  sudo usermod -aG vboxusers stephane   The end result is I'm no longer in the groups I should be in.  Including whatever group is required to run "sudo".  When I run any command as sudo now, I get the following:  $ sudo ls [sudo] password for stephane:  stephane is not in the sudoers file.  This incident will be reported.   Is there a way to fix this, or do I need to re-install from scratch again? . It is a mathematical expression/sequence/set of numbers with the arrow exactly under any one of the numbers (with or without n= 0). How to do it in latex? Any of the up arrow types (single line or double line) shown in the figure is okay. In Unity3D, how do I create an efficient scratch card effect? I want to create a scratch-card-like effect in new Unity UI's new Image tag.  I know it's possible with setPixels, but that's prohibitively expensive on mobile devices.  Something like this:    I'd like the user to be able to drag on any part of the image to "scratch off" the top layer and reveal the content underneath it.  How can I do this? Fundamental group of a torus with points removed Removing blocks from configuration files? What would you call a word that doesn't exist in or translate well into another language? I've run into this situation several times, being a native Spanish speaker.   There are some words you just can't translate into another language. Is there a particular word to describe this?  I'm not refering to idioms.  Also, if its a noun, people tend to use them by surrounding them in quotes. Is this appropiate?  Example:     I arrived at around 5 pm and had some quesadillas.   Edit:  I also meant to cover words that exist in English, but cannot be translated into another language.   Example:      There isn't a word for "drive-thru" in your language. Looking for a title of a sci-fi novel or story where a government department's job was to slow things down How to drive multiple LEDs from a Li-ion battery (with varying voltage)? How can I extract a predetermined range of lines from a text file on Unix? I have a ~23000 line SQL dump containing several databases worth of data. I need to extract a certain section of this file (i.e. the data for a single database) and place it in a new file. I know both the start and end line numbers of the data that I want.  Does anyone know a Unix command (or series of commands) to extract all lines from a file between say line 16224 and 16482 and then redirect them into a new file? EM wave generation from different frames of reference Does more reflective aluminum foil make a room cooler compared to less reflective foil? Aluminum foil is said to be not absorbing light at all. It reflects light. So, does it mean that a more shiny aluminum foil will reflect more light and thus make the room more cooler as compared to less shiny foil?  If yes, then where does unreflected light go in case of less shiny aluminum foil?  Does less shiny and more shiny actually make a difference? Why?  In order to keep whole room cool will it help if I stick the foil to the outside of wooden door (exposed to the sunlight) too? How can I access the "Open command window here" option in Windows without holding shift? Plotting heat equation in a Manipulate expression Question mark or bold citation key instead of citation number "Can/may/will you help me with this?" Which word to use when we ask for help?  Some conditions:     We know that the person asked is able to do it. We don't know if the person asked is able to do it. Proving the inequality $\frac{n^k}{k^k}\leq\binom{n}{k}\leq\frac{n^k}{k!}$ involving binomial coefficient. What is the best way of proving inequalities including binomial coefficients in general? Lets look at this example:     $$\frac{n^k}{k^k}\leq\binom{n}{k}\leq\frac{n^k}{k!}$$   What I started with is:  $$\binom{n}{k}\frac{1}{n^k}\leq\frac{1}{k!}$$ $$\frac{n!}{k!(n-k)!}\frac{1}{n^k}\leq\frac{1}{k!}$$ $$\frac{(n-1)!}{(n-k)!n^{k-1}}\leq1$$ This is where I got stuck. How can I prove that is is lower than or equal to 1? Could you give me a hint? My primary server with SQL Server 2005 broke down, so I've started up the log-shipped database on the secondary server. The database is live on the secondary server, and I just need to remove the log shipping settings for it, while the primary server is no longer accessible.  It seems that the sp_delete_log_shipping_secondary_database stored procedure should be executed on the secondary server to do this, which "removes a secondary database and removes the local history and remote history", as it is stated on .  Would this also remove the database itself? Or only the log shipping settings for it? And what will it do when the primary server is not accessible?  I must not loose the database on the secondary server, as it is already in use. What happens when yellow light is passed through a prism? What happens when secondary colors like yellow,green and magenta are passed through a prism? Will it split into its component colors(for example yellow split into green and red)?If yes why we are observing secondary colors in the visible spectrum obtained when white light(composite light) is passed through a prism? Possible Duplicate:          I know that I have to find the number of factors of $5$'s, $25$'s, $125$'s etc. in order to do this. But how can you derive such a formula for any number $n$?