I am trying to install Skype using the command  dpkg -i skype-ubuntu-precise_4.3.0.37-1_i386.deb   It gives me a error:  dpkg: error: requested operation requires superuser privilege   How can I assign superuser privilege to current user so that I can run command without sudo?  Here is my /etc/sudoers file:  # # This file MUST be edited with the 'visudo' command as root. # # Please consider adding local content in /etc/sudoers.d/ instead of # directly modifying this file. # # See the man page for details on how to write a sudoers file. # Defaults    env_reset Defaults    mail_badpass Defaults    secure_path="/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/snap/bin"  # Host alias specification  # User alias specification  # Cmnd alias specification  # User privilege specification root    ALL=(ALL:ALL) ALL  # Members of the admin group may gain root privileges %admin ALL=(ALL) ALL  # Allow members of group sudo to execute any command %sudo   ALL=(ALL:ALL) ALL   # See sudoers(5) for more information on "#include" directives:  #includedir /etc/sudoers.d   When I run the following command  sudo adduser ehsaan sudo   it gives an error:  The user `ehsaan' is already a member of `sudo'.
I have no root access on this machine.  I would like to know if there is a way I can download Ubuntu packages and install them as non-root?  Probably in my ~/bin or ~/usr/share or something like that? Would that work?
PostgreSQL multi-column unique constraint and NULL values I have a table like the following:  create table my_table (     id   int8 not null,     id_A int8 not null,     id_B int8 not null,     id_C int8 null,     constraint pk_my_table primary key (id),     constraint u_constrainte unique (id_A, id_B, id_C) );   And I want (id_A, id_B, id_C) to be distinct in any situation. So the following two inserts must result in an error:  INSERT INTO my_table VALUES (1, 1, 2, NULL); INSERT INTO my_table VALUES (2, 1, 2, NULL);   But it doesn't behave as expected because according to the documentation, two NULL values are not compared to each other, so both inserts pass without error.  How can I guarantee my unique constraint even if id_C can be NULL in this case? Actually, the real question is: can I guarantee this kind of uniqueness in "pure sql" or do I have to implement it on a higher level (java in my case)? How to prove $\int_{-\infty}^{+\infty} f(x)dx = \int_{-\infty}^{+\infty} f\left(x - \frac{1}{x}\right)dx?$ If $f(x)$ is a continuous function on $(-\infty, +\infty)$ and $\int_{-\infty}^{+\infty} f(x) \, dx$ exists. How can I prove that $$\int_{-\infty}^{+\infty} f(x) \, dx = \int_{-\infty}^{+\infty} f\left( x - \frac{1}{x} \right) \, dx\text{ ?}$$ Why doesn't the Enterprise use stealth/invisibility technology like the Romulans and Klingons? The stealth mode of starships plays a huge role in many Star Trek films and episodes and is a strong advantage in combat. I remember an episode revealing that the Federation developed a secret stealth technology (afair on Riker's former ship with another captain appearing in this episode) that even made it possible to fly with the ship through matter.   Nonetheless, while stealth technology seems standard for Romulans, Klingons (Ferengi, Vulcans?) and does not break any intergalactic laws (do these exist at all?), the Federation doesn't use it? Is the function strcpy always dangerous? Are there names for consonant-shifts when suffixes are added? Back in the dark days when I used to run windows I used to use MindJet Mindmanager and I found it to be very good.  Since I have been using Ubuntu as my main operating system I have been trying to find a replacement mind map software to use but have not had any luck finding a good replacment.  So far I have tried VYM, kdisset and Semantik. I have either found them not to be very good or have a nasty habit of crashing.   So I was wondering could anyone recommend good mind mapping software to use under Ubuntu? If I run history, I can see my latest executed commands.  But if I do tail -f $HISTFILE or tail -f ~/.bash_history, they do not get listed.  Does the file get locked, is there a temporary location or something similar? Why is $X^4+1$ reducible over $\mathbb F_p$ with $p \geq 3,$ prime Occasionally, I've come across a webpage that tries to pop open a new window (for user input, or something important), but the popup blocker prevents this from happening.  What methods can the calling window use to make sure the new window launched properly? Proof of A ⊆ C and B ⊆ C ⇔ A ∪ B ⊆ C I know that this is valid because by thinking about it, you can see it's true, but I'm just not sure how I would go about actually proving it mathematically. I've kind of tried proof by contradiction, since that's what I use most of the time, but it doesn't seem to work.    In my mind, A ∪ B ⊆ C kind of just implies that A ⊆ C and B ⊆ C. How to justify $\phi(n) \ge \sqrt{n}$ If $\phi(n)$ is the Euler-totient function, how can I show that $\phi(n) \ge \sqrt{n}$? How do I install LibreOffice 4? I want to download and install .  How can I do this? How do I access $HOME/storage Termux directory on Android Pie with a GUI File Explorer?  In Termux I print the working directory with pwd and it shows $HOME/storage as:  /data/data/com.termux/files/home   My internal storage looks like this:  . ├── Alarms ├── Android |   ├──data |   |  ├── ... |   |  ├── com.termux |   |  |   └── files |   |  |       └── 0 items |   |  └── ... |   └── ... ├── DCIM ├── Download └── ...   My external storage looks like this:  . ├── Android |   ├──data |   |  ├── ... |   |  ├── com.termux |   |  |   └── files |   |  |       └── 0 items |   |  └── ... |   └── ... └── LOST.DIR   Neither my internal storage, nor my sd card, contain a /data/ directory at the root level. Where is this /data/ directory? For that matter, where is the root /storage/ directory? Where is the root /emulated/ directory? Where are any of these directories and why cant I access any of them? When a user has the  privilege, they can click on the post score to see the individual counts for upvotes and downvotes.  When a user doesn't have this privilege this functionality isn't present, except after loading newly added answers without refreshing the page. After clicking the "new answers to this question" link the click functionality to view vote counts is added to all posts, though actually clicking on it results in a dialog stating that an error occurred (I'd assume due to not having the required reputation).  May be related to the fix for this previous bug report: Computer unstable at lower temperatures My computer is playing some strange joke at me, and I'm at a loss.  Everybody knows that hot temperatures causes many components to become unstable and even cause damage. When I built this machine, I was careful to do a bunch of experiments with different airflow configurations, with CPU-and-GPU intensive benchmarks running, and measuring the temperature at different points to find the best configuration.  Generally, the internal temperature of this machine is very close to ambient temperature (with 2 exceptions: the GPU always runs ~10°C above ambient, and the CPU goes to at most ~12°C above ambient when running CPU-intensive applications).  Now comes the problem: at really cold mornings. At cold mornings (~10°C (50°F) or below), the system shows really strange general instability. Beeps from the BIOS, the operating system displays strange messages about memory corruption and PCI devices that failed to initialize, and then, everything hangs. The computer hangs to the point that all USB devices turn of. Hitting the Reset button blanks the screen but the mainboard fails to proceed to the boot.  I never thought that low temperatures could cause computer instability. And 10°C is not that cold, it is still within operating temperatures of all components as far as I checked.  I'm quite sure it is related with the temperature. There were too many cold and warm mornings that demonstrated that the problem only showed in the cold ones. I'm working around this problem by letting the computer sit at the GRUB menu for some 5-10 minutes before letting the OS start, or blowing hot air inside the case if I'm in a hurry.  I don't know what should I approach next to find the source of this problem. Since it is difficult to reproduce (I need a cold morning, and the computer must be cooled down (powered off for many hours)), I need to plan ahead the experiment, since it stabilizes after a few minutes on.  Machine is an ASUS P5VDC-X equipped with Intel P4 64-bit 3GHz, 2GB of DDR2 RAM, a 500W PSU and an nVidia GeForce 9600GT. Everything else was already disconnected/removed before and the problem persisted, so the problem should be in one of these remaining parts.  Any help is appreciated! Dini's Theorem - Proof. I'd like to prove the following:  If $f_j$ are continuous functions on a compact set $K$, and $f_{1}(x) \leq f_{2}(x) \leq \dots$ for all $x \in K$, and the $f_j$ converge pointwise to a continuous function $f$ on $K$ then in fact the $f_j$ converge uniformly to $f$ on $K$.  Attempt:  Let $g_{j}(x) = f(x) - f_{j}(x)$ for all $j$. Then, since $f_j \rightarrow f$ pointwise, we see $g_j \rightarrow 0$ pointwise.  Now, let $\varepsilon &gt; 0$ . And examine { $x \in K : g_{j}(x) &lt; \varepsilon$ }.  I've been told that the next step should be to  show that { $x \in K : g_{j}(x) &lt; \varepsilon$ } is equal to the intersection of $K$ with some open set $U_j$. But I'm not certain why this is true?   Advice? Insight? Better HTTPS support for Stack Exchange sites So it looks like Stack Exchange now supports HTTPS (to some extent). Which is awesome! But there are a few problems, the main one being that some content is delivered over the CDN, which is plain HTTP. This causes browsers to complain about "unsecured content": Putting a piece of code in between two html tags in Solaris On a solaris HTML file, how do I insert between an html tag and head tag? through bash scripting.  I have an html tag that looks like this:  &lt;html xmlns="http://www.w3.org/1999/xhtml" xmlns:arf="http://scap.nist....-format/1.1" lang="en"&gt;   I want to insert a script written in text file, inside this 'SOLARIS' run HTML file, AFTER the long &lt;html....&gt; tag and BEFORE &lt;head&gt; tag, meaning BETWEEN the two tags, How do I do that?  I want to test using the bash commands to do it for one file at a time as well as multiple file in a folder directory. Will I have to use the folder path in my BASH code? Will I have to use FOR loop or interation in my BASH code? What would be the right code. Note: it is SOLARIS run html file not LINUX one. The name of my HTML file is report.usc20.html.  These are the lines of script that I want to use that are in my backbutton_and_scroller_script.txt file:  &lt;div id="button"&gt;&lt;a href="http://.....index.php"&gt;Back To The Hardening Page&lt;/a&gt;&lt;/div&gt; &lt;script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.3/jquery.min.js"&gt;&lt;/script&gt; &lt;script type="text/javascript" src="http://arrow.scrolltotop.com/arrow78.js"&gt;&lt;/script&gt; &lt;noscript&gt;Not seeing a &lt;a href="http://www.scrolltotop.com/"&gt;Scroll to Top Button&lt;/a&gt;? Go to our FAQ page for more info.&lt;/noscript&gt; If two variables have 0 correlation, why are they not necessarily independent? Are zero correlated variables independent under special circumstances ?  If possible, I am looking for an intuitive explanation, not a highly technical one. The order of words in a clause: "tell me who is the real man" vs. "tell me who the real man is"