I got the GRUB menu, chose Advance, but in that menu, I don't see the recovery mode option. I only have two different options on the Linux version. Please help, as I forgot my password, and need to access the terminal to restart the Samba file sharing service for my Ubuntu server.
I want to boot Ubuntu into recovery mode but there is no grub menu entry allowing me to do so. I pressed e and now I am able to edit boot options. It looks like that:  setparams 'Ubuntu , with Linux 3.6.0-26-generic'  recordfail gfxmode $linux_gfx_mode insmod gzio insmod part_msdos insmod ext2 set root='(hd0,msdos5)' search --no-floppy --fs-uuid --set=root &lt;uuid&gt; linux /boot/vmlinuz-3.5.0-26-generic root=&lt;uuid&gt; ro ipv6.disable=1 quirt splash $vt_handoff initrd /boot/initrd.img-3.5.0-26-generic   The  documentation says:     Boot to the recovery mode even if it is not listed on the menu:         Remove existing kernel options from the linux line and add single      But this sentence doesn't make any sense, maybe the wiki page is broken somehow. How to modify the boot menu to boot directly into recovery mode?  Note: I don't have access to grub config or anything else, only the boot menu edit page is available.
Populating cascading dropdown lists in JSP/Servlet Any $B \subset \{10,11,...,99\}$, with $|B| =10$ has two subsets such that $\sum_{a \in B_1} a = \sum_{b \in B_2} b$ Let there be $B \subset \{10,11,...,99\}$, with $|B| =10$. I need to prove, using the pigeonhole principle, that there are at least two disjoint subsets of $B$ (and none empty) where the sums of their elements are identical. I.e. $\exists B_1 \ne \varnothing, B_2 \ne \varnothing$ such that $B_1 \bigcup B_2 = B$, $B_1 \bigcap B_2 =\varnothing$ and $$\sum_{a \in B_1} a = \sum_{b \in B_2} b$$ I observe the following strange characters ^@ in syslog at the time when my machine freezes.  Then i have to hardboot my machine.  What could be wrong any ideas?  Oct 12 12:20:52 nanak-P570WM anacron[1074]: Normal exit (1 job run) ^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@  Oct 12 12:24:28 nanak-P570WM kernel: imklog 5.8.11, log source = /proc/kmsg started. Oct 12 12:24:28 nanak-P570WM rsyslogd: [origin software="rsyslogd" swVersion="5.8.11" x-pid="543" x-info="http://www.rsyslog.com"] start Saving Photoshop multilayer file to PDF without layers size difference Why is it that when I save a file that has many, many layers to a PDF without layers as a copy that the file size is larger than flattening the layers and then saving the file as a copy to PDF? 19Mb vs. 5Mb?? Wouldn't saving a file without layers be the same as flattening the layers and then saving the file?? Can anyone explain this? Object-orientation in C What would be a set of nifty preprocessor hacks (ANSI C89/ISO C90 compatible) which enable some kind of ugly (but usable) object-orientation in C?  I am familiar with a few different object-oriented languages, so please don't respond with answers like "Learn C++!". I have read "" (beware: PDF format) and several other interesting solutions, but I'm mostly interested in yours :-)!    See also We're all familair with this beautiful proof whether or not an irrational number to an irrational power can be rational. It goes something like this:  Take $(\sqrt{2})^{\sqrt{2}}$  If it's rational, then you proved it, if it's irrational, take $((\sqrt{2})^{\sqrt{2}} ){^\sqrt{2}} = 2$ and you've proved it.  I'm wondering if you can raise $\pi$ or $e$ to a certain non-trivial real power to make it rational? And if not, where is the proof that it can't be done?   p.s. - I almost left out the real part, but then I realized that $e^{i\pi} = -1$. When is a review task "completed" or "invalidated"? I've noticed that the number of reviews required to remove a post from a queue varies. For example, to accept/reject a suggested edit, you need two votes of the same kind. If the votes are conflicting, the number goes higher. This seems to be the case for the other queues as well. (Additionally, I think that a mod-review is binding) So, my question is: what are the criteria for a review to be marked as a &quot;completed&quot; review? Also, when is a review considered invalidated (i.e. &quot;no longer reviewable&quot;)? Formerly When is a post removed from a review queue?. Persistent do not disturb toggle in Yosemite possible? How can I determine whether a 2D Point is within a Polygon? I'm trying to create a fast 2D point inside polygon algorithm, for use in hit-testing (e.g. Polygon.contains(p:Point)). Suggestions for effective techniques would be appreciated. If we remove the square in the upper right corner of a $8\times 8$ chessboard.  The question is: Is it possible to cover the entire remaining area, with $1\times 3$ chocolate bars? (they can be laid on the chessboard vertically and horizontally aswell)  For the answer: We know that there will be $63$ squares left on the chessboard, of which $32$ are white and $31$ are black, since the one in the upper right corner was black. $63$ is divisible by $3$, so it could be possible to cover the area, but that doesn't prove that an arrangement exists to do it. I'm not sure how to continue and am seeking help. Thanks. How to export data as CSV format from SQL Server using sqlcmd? What is the single most influential book every designer should read? What is the single most influential book every designer should read? I've come across a small issue which occurs when a question has been closed but the question itself or one of its answers are being edited.  Steps to reproduce:   Visit a closed question. (even closed years ago)   In a different tab or browser, edit the question or one of its answers. "an edit has been made to this post; click to load" message will appear above the edited post in the first tab/browser, click it. The .question-status div becomes hidden, which includes the closed notice below a question and, for a duplicate-closed question, the list of duplicates above the question body. This gives the appearance that the question is no longer closed (until you refresh).   Some screenshots:                I know it isn't common/important but it did confuse me when looking at a particularly bad question - I thought it had been reopened.   Is this an intentional feature? If so, what was the thinking behind it?    Another example  Before    After How do you use a gray card? There are already   on how to make a gray card, but unfortunately my ignorance goes deeper than that.  How do you use a gray card? Show that $n-m$ is a multiple of 9 when $n$ and $m$ have same digits Limiting range of value types in C++ Suppose I have a LimitedValue class which holds a value, and is parameterized on int types 'min' and 'max'.  You'd use it as a container for holding values which can only be in a certain range.  You could use it such:  LimitedValue&lt; float, 0, 360 &gt; someAngle( 45.0 ); someTrigFunction( someAngle );   so that 'someTrigFunction' knows that it is guaranteed to be supplied a valid input (The constructor would throw an exception if the parameter is invalid).  Copy-construction and assignment are limited to exactly equal types, though.  I'd like to be able to do:  LimitedValue&lt; float, 0, 90 &gt; smallAngle( 45.0 ); LimitedValue&lt; float, 0, 360 &gt; anyAngle( smallAngle );   and have that operation checked at compile-time, so this next example gives an error:  LimitedValue&lt; float, -90, 0 &gt; negativeAngle( -45.0 ); LimitedValue&lt; float, 0, 360 &gt; postiveAngle( negativeAngle ); // ERROR!   Is this possible?  Is there some practical way of doing this, or any examples out there which approach this? Using single quote by curly braces in String.format in Dynamic SOQL I'm struggling to use String.format to replace a token with a value when the token is within single quotes:  Example:  String query = String.format('SELECT Id FROM Availability WHERE Person__c = \'{0}\'', personId);   String query is equal to:  SELECT Id FROM Availability WHERE Person__c = {0}   Rather than:  SELECT Id FROM Availability WHERE Person__c = '234567890' Way to detect frozen video with ffmpeg? Is there a way to detect frozen video with ffmpeg? I only need to know if there are rather large regions of frozen video, say 10 seconds or more.   I'm familar with the  filter.   Maybe you could first difference adjacent frames, then use blackdetect to tell whether the difference has not changed? I'm not sure how to perform the difference though. How long does it take for a black hole to form for an external observer? The well-known fable of an astronaut sending signals out to an external observer while falling toward an event horizon states that the time lapse between such signals becomes greater even if in the astronaut sends them out periodically (as judged in his inertial frame). When viewed from earth and weighing time-dilation due to the gravitational field of the collapsing star, how is it possible that a black hole can form in finite time (for any external observer) if it takes an infinite amount of time to "see" events occurring at the event horizon? Mcrypt extension is missing in 14.04 server for mysql The php mcrypt extension on ubuntu 14.04 shows that it is installed properly, but phpmyadmin says:   The mcrypt extension is missing. Please check your PHP configuration.   My current php config is . If you need anymore information, please contact me through the comments.  $ sudo apt-get install php5-mcrypt     Reading package lists... Done     Building dependency tree            Reading state information... Done     php5-mcrypt is already the newest version.     0 upgraded, 0 newly installed, 0 to remove and 0 not upgraded.