permissions – Linux “ls -Z” shows question mark for security context

I’ve got some files that aren’t being served on a site, and assuming it was a permissions issue I ran ls -Z but keep seeing ? in place of the security context:

-rw-rw-r--  pete pete ?                                index.cfm

I get this running sudo as well. Can anyone explain what the ? means or what I need to do to fix the file?

I’ve tried using sudo chcon system_u:object_r:httpd_config_t:s0 index.cfm to match the other permissions of files in the folder, but that doesn’t help. Also if I try to recreate the file I get the ? again

cat index.cfm > index.bkp
sudo ls -Z
-rw-rw-r--  pete pete ?                                index.bkp
-rwxrwxrwx. pete pete system_u:object_r:httpd_config_t:s0 index.cfm
mv index.bkp index.cfm
-rw-rw-r--  pete pete ?                                index.cfm

How I get rid of exclamation mark near thread at slack? I cannot find the unsent message

I get exclamation mark near thread. The point is unsent message but I cannot find it.
When I hover on exclamation mark I can get snippet of the unsent message, but when I search for it, I cannot find it (probably because it not sent.
This is any solution?

I read twit from slack – but it not help

How to copy and paste numbers with “`” mark and use them in calculations, without using N or setting precision every time

Suppose we have run a calculation and get a number like


If we then copy-paste this number and do a calculation like


Mathematica will give a red 0. and an error about no significant digits. Why does this happen (note:putting a “`” on the 1 fixes the problem, so perhaps I am mixing different types of numbers?)

Even more worrisome to me, is that perhaps my calculations in some long program will be messed up from such an issue.

Is there a global setting that I can change (for example, at the top of a document or something), so that mathematica can properly do such calculations (with some “acceptable” amount of error?

I realize that if I instead do


Mathematica will do the calculation. I also realize that this is an issue with precision.

However, I have tried reading the documentation and some questions on this site, and I don’t understand either 1) What the issue is, 2) Whether I can globally set precision so that such calculations work out with some acceptable amount of error.

For example, I believe using N as above, means mathematica uses machine precision. Is this machine precision good though? Or bad? I tried reading through the documentation and I can’t figure it out.

I realize that there are questions about this on the site, and that mathematica has documentation on this, but honestly I cannot understand it well. So here I am specifically looking for if someone can explain how I can deal with this, in a more simple manner

Edit: One more thing. The help documentation here makes me think arbitrary precision numbers are better (since it talks about arbitrary precision numbers maintaining a pertaining number of correct digits, and machine precision numbers needed to be checked for correctness). If that is the case though, how come arbitrary precision numbers don’t work in the simple example, but using N for machine precision does?

unity – Mark positions of spawnpoint in editor

I am creating a digital boardgame, which consits of muliple boards, between which the gamepieces are moved by the players.

The script of the game board needs a 2D array of positions to know where to move a gamepiece when it recives one.
Currently to mark the positions on the game boards, I added placeholder gameobjects to the prefab and named them “spawnpointd”.In the Awake() method I use Transform.Find() to search for those gameobjects. Then, after I save their positions I call Destroy() on them, so they do not show up in the game.

I see two problems:

  1. This is done for all Instantiated game board, altough the positions are the same on all of them.
  2. I read that using Transform.Find() is heavily discourged by the experts in the community.

I wish to store the spawnpoint positions in a static array, so all instances refer to the same data. Furthermore I wish to easily modify these positions in the editor with visual help.

I tried serializing static members, but those do not show up in the editor to be able to modify.

    public static int TestNumber;

How to make static members visually changeable from the Unity editor?

iOS 14 Messages swipe left to right to mark read

I have noticed that swiping a message left to right in iOS Messages is suddenly pinning it instead of marking it read and it appears that the is no longer a quick way to mark a message read without opening it.

I am wondering if there is a way to change the behaviour back to how it was (mark message read by swiping left to right)?

Didn’t find any tips on that by googling.

automata – Is ${varepsilon}$ a conventional way to mark the empty language?

No, that’s the language containing one string: the empty string, which is very much distinct from the empty language. The finite state machine on the left accepts language ${}$, the finite state machine on the right accepts language ${varepsilon}$. They are not the same.


If a lot of students are confused maybe explicitly show the difference in an exercise/during a lecture.

❕NEWS – Mark Cuban Increases Buys in This Altcoin | Proxies-free

A detail emerged when Mark Cuban, owner of Dallas Mavericks, promoted her digital collection on Rarible at Ethereum wallet address on her social media account.
According to CoinGecko, Cuban has staked 450 Aave (AAVE) tokens. In the last seven days, it has yielded 80% and the value of AAVE tokens in their hands has reached $ 128,500.
Cuban currently has 947 Aave tokens in his wallet address and he has staked all of them. This increased the value of their Aave token to $ 460,000.
What do you think of Mark Cuban’s AAVE investment?

❕NEWS – Jeff Bezos gains as Elon Musk, Mark Zukerberg and others loss about $14.7 billion. | Proxies-free

The pandemic which is increasingly made most of the wealthiest men in the world more richer especially Jeff Bezos, Elon Musk, Mark Zukerberg and others has also made most of them poorer except for Jeff Bezos, this was due to the increase in the Corona virus cases and there is no plan for the second stage stimulus package for the citizens.
The loses incurred by the nine wealthiest men was to tune of $14.5 billion while a gain was in favor of Jeff Bezos to a tune of $159 million .

Mark Zukerberg lost $2.8 billion.
Larry of Oracle lost $2.6 billion
Larry page lost $2 billion
Sergey Brin lost $1.9 billion
Bill gate lose $1.8 billion
Buffet lost $1.5 billion
Alice Walton loss $635 million
Elon musk lost $66 million.

The stock market was largely responsible for their huge losses, I believe they will bounce back!!

❕NEWS – Mark Cuban says dogecoin will soon but $1 | Proxies-free

Dallas Mavericks owner , Mark Cuban has said that If they can sell another 6,556,000,000 DOGE worth of Mavs merch, dogecoin has the possibility of hitting 1$ .

It has not been more than three days since the firm accepted dogecoin as payment method , and they have received up 20,000 dogecoin for Mavs merch. This is an indication that people are willing to invest more in dogecoin in order to invest in the company.
what do you think of this prediction ?

lighting – Light for Canon EOS 6D Mark ii

Next week I will receive Canon EOS 6D Mark ii. It’s my first camera.

I have also bought Canon EF 100 f/2.8L Macro IS USM.
I am very interested in doing macro photography.

My question is about light for macro photography and that particular camera – what would you recommend?
I’ve found things like this but I am really not sure whether this is good solution or not.

Mostly I will be shooting out in nature. So best solution would be something easy to carry in backpack and at the same time offering good lightning.