Both bash and zsh support a shorthand of not placing a command in history if you prepend it with a space.  This works great across sessions (if you've setopt histignorespace).  However, the command is still in the current session's history.  How can I avoid placing a command in the current session's history (or remove if after executing it)?
Is there any way to keep a command from being added to your history? I have a command that I want to keep out of my history file, and I really don't care to have it there when I search the history stored in memory, though that's less of a concern. Is there any way to prevent this, or do I just have to go back and edit my history file.  update: I didn't realize this might be shell-specific. My shell is zsh. You're welcome to answer for other shells so people know how to do this in their shell.
I'm flying to Tokyo. The flight was sold through Finnair. The first leg is operated by American Airlines. The second and final legs are operated by Finnair.  When I checked in online, it said that some airports on my journey (didn't say which one) don't allow mobile boarding passes?? Meaning I will need a physical copy.  Unfortunately I don't have easy access to a printer. Will I still be able to print all my boarding passes at the airport even though I already checked in online? Here is the documents needed.     Here are the documents needed.       Which is grammatically correct and why? My guess would be the second one because of the plural form. Questions on "All Horse are the Same Color" Proof by Complete Induction I'm bugged by the following that's summarized on p. 109 of .     False theorem: All horses are the same color.      Proof by induction:      $\fbox{$P(n)$ is the statement: In every set of horses of size $n$, all $n$ horses are the same color.}$   $\fbox{Base Case or $P(1)$:}$ One horse is the same color as itself. This is true by inspection.   $\fbox{Induction Step:}$ Assume $P(k)$ for some $k \geq 1$.   $\fbox{Proof of $P(k + 1) :$}$   Since $\{H_1, H_2, ... , H_n\}$ is a set of $n$ horses, the induction hypothesis applies to this set. Thus, all the horses in this set are the same color.   Since $\{H_2, H_3, ... , H_{n+1}\}$ is also a set of $n$ horses, the induction step likewise holds for this set. Thus, all the horses in this set are the same color too.         Therefore, all $n +1$ horses in $\{H_1, H_2, H_3, ... , H_n , H_{n+1}\}$ are the same color. QED.   The issue the instructor was trying to point out is clearly valid. For the case $n = 1$, there is only ${H_1}$. So this case says nothing about possible overlapping elements of each set of $(n + 1)$, for instance $H_2$ in the above proof.    But it was proposed in the class discussion that this was the only problem. Had you been able to prove $P(2)$ true, then a proof of the above format would have been fine.    My interpretation is that yes, you could prove all horses are the same color, if you can prove that any set of two horses will be the same color. But this format would not work.  Why not? The problem I see is that the above proof is for the existence of at least one particular pair of sets of horses of sizes $n$ and $n + 1$, such that in each set, all horses are the same color.  Particularly when the set of size $n$ is a subset of the set of size $n + 1$.  In order to prove the induction step, don't you need to prove that sets of sizes $n$ and $n + 1$, do not necessarily contain the same, overlapping elements?  You could prove that any horse can be added to a set of 2 horses.  Take the last two, and they must be the same color, and so on.  Wwhatever color the first two happen to be, all other horses must thus be the same color.    Am I misinterpreting the example, or am I making a logical error? Thanks in advance. Parsing domain from a URL How can I remove duplicate rows? What is the best way to remove duplicate rows from a fairly large SQL Server table (i.e. 300,000+ rows)?  The rows, of course, will not be perfect duplicates because of the existence of the RowID identity field.  MyTable  RowID int not null identity(1,1) primary key, Col1 varchar(20) not null, Col2 varchar(2048) not null, Col3 tinyint not null I am not a administrator and I would like to find the administrator password. I would not like to reset it however. Is there anyway to find and not reset the administrator password? From the spell description:     Sleep (...) Creatures within 20 feet of a point you choose within range are affected in ascending order of their current hit points (ignoring unconscious creatures). Starting with the creature that has the lowest current hit points,(...) Subtract each creature’s hit points from the total before moving on to the creature with the next lowest hit points. A creature’s hit points must be equal to or less than the remaining total for that creature   to be affected. Undead and creatures immune to being charmed aren’t affected by this spell. (PH p.276)   Now, to build the ascending order of their current hitpoints, the spell instructs to count everyone in area of effect, but only ignore unconscous creatures. Then later on it says that Undead and creatures immune to being charmed aren't affected.  Are those two latter kinds of creatures excluded from the roll of current HP by default? Following the "if they were it would say so" philosophy of Sage Advice, it doesn't seem so to me. Compactness of $A:=${$f \in C[0,1], |f|_\infty \le K, |f'|_\infty \le M$} Here we use infinity norm as metrics for $C[0,1]$. The professor claims that this set is compact. I can show this set is relative compact by Arzela Ascoli, i.e., for each subsequence there is a further sub-subsequence that uniformly converges to a continuous function on $[0,1]$. But it is not intuitive to me why this set is compact, i.e. the limiting function also satisfies $|f'|_\infty \le M$. Is it true that $A$ is close and therefore compact? Error "WIF10201: No valid key mapping found" when trying to create claims from SAML How to cite a source that has vanished due to link rot? My colleague is writing a manuscript about a subject that is rarely reported in the mainstream literature (predation events). A few years ago on a fishing forum she found a photograph that demonstrated this phenomenon pretty well and saved it to her computer, but unfortunately between then and now the original source has vanished: Google Reverse Image Search can't locate it, the website is no longer running and is also unavailable in the Internet Archive. The original URL to the photo was also not retained.  What's the proper way to cite this source? It's not critical to include but it would definitely improve the final manuscript. I recently printed a paper that asks to prove the "amazing" claim that for all $a_1,a_2,\dots$  $$\sum_{k=1}^\infty\frac{a_1a_2\cdots a_{k-1}}{(x+a_1)\cdots(x+a_k)}=\frac{1}{x}$$  and thus (probably) that  $$\zeta(3)=\frac{5}{2}\sum_{n=1}^\infty {2n\choose n}^{-1}\frac{(-1)^{n-1}}{n^3}$$  Since the paper gives no information on $a_n$, should it be possible to prove that the relation holds for any "context-reasonable" $a_1$? For example, letting $a_n=1$ gives  $$\sum_{k=1}^\infty\frac{1}{(x+1)^k}=\frac{1}{x}$$  which is true.  The article is Gauss's Lemma for polynomials claims that a non-constant polynomial in $\mathbb{Z}[X]$ is irreducible in $\mathbb{Z}[X]$ if and only if it is both irreducible in $\mathbb{Q}[X]$ and primitive in $\mathbb{Z}[X]$.   I wonder if this holds for multivariable case.      Is it true that a non-constant polynomial in $\mathbb{Z}[X_1,\dots,X_n]$ is irreducible in $\mathbb{Z}[X_1,\dots,X_n]$ if and only if it is both irreducible in $\mathbb{Q}[X_1,\dots,X_n]$ and primitive in $\mathbb{Z}[X_1,\dots,X_n]$?    Thank you for your help. I was reading . They are performing a logistic regression (with R). At some point they calculate the probability of getting a residual deviance higher than the one they got on a $\chi^2$ distribution with degrees of freedom equal to the degrees of freedom of the model. Copying-pasting from their website...   &gt; glm( cbind(using,notUsing) ~ age + hiEduc + noMore, family=binomial)  Call:  glm(formula = cbind(using, notUsing) ~ age + hiEduc + noMore,            family = binomial)   Coefficients: (Intercept)     age25-29     age30-39     age40-49       hiEduc       noMore       -1.9662       0.3894       0.9086       1.1892       0.3250       0.8330    Degrees of Freedom: 15 Total (i.e. Null);  10 Residual Null Deviance:      165.8  Residual Deviance: 29.92        AIC: 113.4        The residual deviance of 29.92 on 10 d.f. is highly significant:  &gt; 1-pchisq(29.92,10) [1] 0.0008828339       so we need a better model     Why does it make sense to compute 1-pchisq(29.92,10) and why does a low probability indicate that something is going wrong with their model? How to recover data from a USB-connected hard disk that shows no partition? register_nav_menus() won't register menus Please help with menu registeration:  I have followed this guide (http://codex.wordpress.org/Navigation_Menus) step by step.  Added the following code to functions.php:  function register_my_menus() {   register_nav_menus(     array('header-menu' =&gt; __( 'Header Menu' ) )   ); }  add_action( 'init', 'register_my_menus' );   But the guide says that this will make the menu appear in the Appearance -> Menus admin screen in the "Theme Locations" box as "Header Menu".  When I go to Appearance -> Menus everything is greyed out and there is no option of "Theme Locations" set fontsize for TikZ figure Smeared creamy look effect i came across a photo where the gradient looks like it s smeared from cream. It is hard to explained by saying so here is the  Let say i create 2 similar shapes with the gradient pattern then adjust the opacity but the edges will still remain. But in the example the edges are appeared to be soft and hard randomly. Thanks in advance ! Preview of CAD files in format .dwg I'm looking for a utility or a program for Ubuntu, and possibly even for Windows that is able to convert a CAD file format .DWG to PDF.   My need is to provide a preview of CAD files, and I thought that the easiest way is to convert them into PDF format, but I'm open to suggestions, even if there is only the possibility to convert them to JPG image file type or PNG would be fine.  What interests me is only to find some solution, no matter if it is commercial or free Infusing olive oil with herbs According to the Wikipedia article on  the sample SD   $$s = \sqrt{\frac{1}{n-1} \sum_{i=1}^n (x_i - \overline{x})^2}$$  is a biased estimator of the SD of the population. It states that $E(\sqrt{s^2}) \neq \sqrt{E(s^2)}$.   NB. Random variables are independent and each $x_{i} \sim N(\mu,\sigma^{2})$   My question is two-fold:   What is the proof of the biasedness? How does one compute the expectation of the sample standard deviation    My knowledge of maths/stats is only intermediate.