fastest way of searching for a text in a file (not file name) including the root volume
Recursive grep vs find / -type f -exec grep {} \; Which is more efficient/faster?
One time pad: why is it useless in practice? The symmetric cryptosystem one-time pad (OTP) seems to be very beautiful since it is perfectly secret according to Shannon. Many books, however, point out the main drawback: one must create a secret key the same length as the plaintext. For this reason, the concept of perfect secrecy has these days been abandoned, and we prefer other cryptosystems.   Now, for example, suppose I want to encode my text message with the ASCII scheme, and moreover suppose that this plaintext is 10 gigabytes long, therefore (using an OTP) the key must be the same length, 10 gigabytes. I think, however, this is a ''sustainable price'' because I'm sure that the ciphertext can't be attacked.  Practically, I don't understand why having such long keys with an OTP is a big disadvantage if we reach "the dream"-- namely, perfect secrecy. Nowadays the storage of information is very easy, so what is the real problem? I can, for example, share the "long key" in person. Remove line containing certain string and the following line How to tell if mains voltage is on with microcontroller? I want to be able to tell if the mains voltage is on or off with an Arduino.   How could I do this safely with minimal components (or components from Radio Shack)? Adaline is 100-something years old, and her daughter appears to be 90 years old. Well, Adaline gave birth to her in her mid 20's, and to be precise, she should be 80.   Anyways, Adaline's old lover's son (Ellis) is probably in his late 20's/early 30's. And Adaline has stopped aging at 29, which is pretty close to Ellis. Her old lover is said to be a few years younger than her and still, his son is so young. Also, Adaline could make him believe that she is the daughter of her own old self.   Then,      how can Adaline's real life daughter be so old?   I can't make sense out of this.  Why is it this way? The age pattern of the actors and actresses is inconsistent. It seems to me that the filmmakers have exaggerated some things. I am making an Android game that is only in portrait screen orientation.  It works great when I run it on my phone, but when I run it on a tablet, even though the screen size is bigger, all of the bitmaps are the same size. Is there any way to make the bitmaps stay the same proportion even on different size screens? I have two given names and one surname. Is it a problem if I omit the surname from my ticket? I have two names as my given name in the passport and I typically just use this as my first and last name. However, my passport has a surname too which I almost never use. Due to this, I mistakenly provided my given name as first and last name.   As per the passport,  Surname : AAAA Given name(s) : BBBB CCCC   In the ticket, First name : BBBB Last name : CCCC  The credit card I've used to make this booking has my name as BBBB CCCC.  Will this create a problem at the travel time?  Update : the airline says that they can't update the name in the ticket. They are saying that since they have made a remark of the passport details boarding will not be a problem but I might face problems at immigration. Do they check name details in itenerary to exactly match passport at the time of immigration? Is that true in your experience?  Update : Travelled without any problem, neither at boarding gate, immigration nor after arrival at border police control. What is a terminal and how do I open and use it? What is a terminal? How do I open a terminal window? How do I use the terminal? Indian CGPA to US GPA system "Any" followed by singular or plural countable nouns? This question has troubled me for ages despite my several attempts of looking it up in dictionaries or usage books. Do we say, "Do you have any ideas" or "Do you have any idea"? I do see an example where "any" means "it doesn't matter who/which/what", therefore "You can borrow any book you like." Also, does it matter between using it in questions and negatives? If $\sum_na_n=\infty$ and $a_n\downarrow 0$ then $\sum\limits_n\min(a_{n},\frac{1}{n})=\infty$ If $\sum_na_n=\infty$ and $a_n\downarrow 0$ then $\sum\limits_n\min(a_{n},\frac{1}{n})=\infty$     My  idea:  $$b_{n}=\min(a_{n},\tfrac{1}{n})\Longrightarrow b_{n}\le a_{n},b_{n}\le\tfrac{1}{n}$$ then I don't know how to go on. Backtrack, Wi-Fi not working I've installed Backtrack 5R3 KDE, and I realized that my wireless is not working, but wired is working fine.  Here's the lshw output:     *-network         description: Ethernet interface         product: RTL8101E/RTL8102E PCI Express Fast Ethernet controller         vendor: Realtek Semiconductor Co., Ltd.         physical id: 0         bus info: pci@0000:02:00.0         logical name: eth0         version: 05         serial: 04:7d:7b:b7:46:f8         size: 100MB/s         capacity: 100MB/s         width: 64 bits         clock: 33MHz         capabilities: pm msi pciexpress msix vpd bus_master cap_list ethernet physical tp mii 10bt 10bt-fd 100bt 100bt-fd autonegotiation         configuration: autonegotiation=on broadcast=yes driver=r8169 driverversion=2.3LK-NAPI duplex=full firmware=rtl_nic/rtl8105e-1.fw ip=192.168.2.2 latency=0 link=yes multicast=yes port=MII speed=100MB/s         resources: irq:42 ioport:2000(size=256) memory:f0404000-f0404fff memory:f0400000-f0403fff   lspci output:      00:00.0 Host bridge: Intel Corporation 2nd Generation Core Processor Family DRAM Controller (rev 09) 00:02.0 VGA compatible controller: Intel Corporation 2nd Generation Core Processor Family Integrated Graphics Controller (rev 09) 00:14.0 USB Controller: Intel Corporation Panther Point USB xHCI Host Controller (rev 04) 00:16.0 Communication controller: Intel Corporation Panther Point MEI Controller #1 (rev 04) 00:1a.0 USB Controller: Intel Corporation Panther Point USB Enhanced Host Controller #2 (rev 04) 00:1b.0 Audio device: Intel Corporation Panther Point High Definition Audio Controller (rev 04) 00:1c.0 PCI bridge: Intel Corporation Panther Point PCI Express Root Port 1 (rev c4) 00:1c.1 PCI bridge: Intel Corporation Panther Point PCI Express Root Port 2 (rev c4) 00:1d.0 USB Controller: Intel Corporation Panther Point USB Enhanced Host Controller #1 (rev 04) 00:1f.0 ISA bridge: Intel Corporation Panther Point LPC Controller (rev 04) 00:1f.2 SATA controller: Intel Corporation Panther Point 6 port SATA AHCI Controller (rev 04) 00:1f.3 SMBus: Intel Corporation Panther Point SMBus Controller (rev 04) 02:00.0 Ethernet controller: Realtek Semiconductor Co., Ltd. RTL8101E/RTL8102E PCI Express Fast Ethernet controller (rev 05) I'm a teacher and I teach at/in school OR at/in a school There are a lot of posts on this topic, but I can't find any answers to my question.  I came across the following two definitions of 'school':        [uncountable] (used without the or a) the process of learning in a   school; the time during your life when you go to a school (British   English)   [uncountable] (used without the or a) the time during the day when   children are working in a school      Source:   I know there are better ways to convey the message, but which sentence would a teacher utter if he was a school teacher teaching students, adults, etc.? What about a janitor, director, and secretary?     I teach at/in school OR I teach at/in a school   The above definitions concern students, and not working individuals like teachers or janitors.  I would appreciate if you also stated whether you're American, Canadian, British, etc. There is a button in the "basic math assistant" which wraps highlighted text in chosen brackets. Is there no keyboard command for this? Intellij shortcut for quick call hierarchy Is there a shortcut key to bring up the call hierarchy of a method inline with the code, in the quick menu format, rather than bringing up the call hierarchy panel? Here is what I do:   restart machine with Windows 8.1 determine "EFI System" partition with the Disk Management utility run command prompt as administrator type diskpart type select disk 0 then select partition 2 then assign open windows explorer windows+e refresh if the drive is not showing F5 try to open drive by double clicking   What I expected to happen:  I can at least look at my EFI partition files.  What happened:    after clicking continue    after clicking "security tab" link, no security tab    What do I need to do to access my EFI partition on Windows 8.1? Setting items to status-completed before they're deployed In several scenarios, including two today ( and ), we have had bugs set to  simply because the fix has been checked in. Just because the code portion has been completed does not mean the work is done, and this can be confusing for users who come across the same problem. Until then it really is  or maybe a tag that doesn't yet exist (status-checked-in?).  Particularly in times like this week, where the stability of the system is a priority, I don't think this status should be set merely because the code has been checked in - it should happen when the code is actually deployed and verified. Currently the devs are being very good about telling us that the code is done but they're not sure when it will be deployed, but I think that is because of the stability issue. I am currently trying to establish a clear picture of pure/mixed/entangled/separable/superposed states. In the following I will always assume a basis of $|1\rangle$ and $|0\rangle$ for my quantum systems. This is what I have so far:   superposed: A superposition of two states which a system $A$ can occupy, so $\frac{1}{\sqrt{2}}(|0\rangle_A+|1\rangle_A)$ seperable: $|1\rangle_A|0\rangle_B$ A state is called separable, if its an element of the (tensor)product basis of system $A$ and $B$ (for all possible choices of bases) entangled: $\frac{1}{\sqrt{2}}(|0\rangle_A|1\rangle_B+|1\rangle_A|0\rangle_B)$ is not a state within the product basis (again for all possible bases). mixed state: Is a statistical mixture, so for instance $|1\rangle$ with probability $1/2$ and $|0\rangle$ with probability $1/2$ pure state: Not a mixed state, no statistical mixture   I hope that the above examples and classifications are correct. If not it would be great if you could correct me. Or add further cases, if this list is incomplete.   On wikipedia I read about      Another way to say this is that while the von Neumann entropy of the whole state is zero (as it is for any pure state), the entropy of the subsystems is greater than zero.   which is perfectly fine. However I also read on wikipedia a criterion for :     Another, equivalent, criterion is that the von Neumann entropy is 0 for a pure state, and strictly positive for a mixed state.   So does this imply that if I look at the subsystems of an entangled state, that they are in a mixed state? Sounds strange... What would be the statistical mixture in that case?  Moreover I also wanted to ask, whether you had further illustrative examples for the different states I tried to describe above. Or any dangerous cases, where one might think a state of one kind to be the other? Problem: A lot of the time I downvote something that clearly shows lack of research or effort on OP's part, and when they edit to improve it, I usually find out pretty late, because there are no notifications to help with that.  Proposition: add a Get notified when this post is edited button/checkbox under a post which you have downvoted (per post, not just all posts ever), so that if there is a significant improvement, you could remove your downvote or even change it to an upvote to show you recognize the improvement.  I believe this would improve public thinking about votes, and make people (who choose to participate like this on the SE sites more often) vote more freely and more often, and everybody else would not think of a &lt;0 post score as a death sentence for their contribution.  I'm not asking to enable this on SO (for a number of obvious reasons), and that's why I propose an opt-in subscription. This would be most useful on lower activity sites like the SE, in my opinion, but who knows.    I want to know if someone has improved their post after a downvote to reinforce the positive behavior and I get -4 on my good intentions? What kind of culture are you trying to cultivate? Please, explain why you disagree without silently downvoting. If you think there's a better way, yes, I want to know your thoughts. How to correctly setup Ubuntu 18.04 LTS installed from mini.iso to use NetworkManager? Does Python SciPy need BLAS?