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Mastering Development

Confusion Regarding pip and conda environment

I am trying to install the twint library into a conda virtual environment. I have to use pip because the library is not at the conda or conda forge channels. twint requires Python 3.6, so I created a new virtual environment with that version. I created that environment following Anaconda’s instructions: conda create –name py36 […]

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Ask Mathematics

Has vol. 3A of Cullis’s “Matrices and Determinoids” been scanned and vol. 3B been archived?

This is a borderline question, but I’m going to risk posing it. Cuthbert Edmund Cullis (1875?-1955?) was a somewhat obscure British mathematician whose opus magnum was a multi-volume treatise called Matrices and Determinoids. While his notation is somewhat idiosyncratic, it was a fairly systematic exposition of most(?) of the linear algebra known by the 1920s […]

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Linux Mastering Development Ubuntu

HDD error : print_req_error: critical medium error, dev sdb, sector 16128

I believe, I have a USB hard drive that’s damaged. When I run dmesg, it shows: [80489.847168] —[ end trace 66bad045bd32e5be ]— [80577.323943] usb 2-1.1: new high-speed USB device number 4 using ehci-pci [80577.434010] usb 2-1.1: New USB device found, idVendor=152d, idProduct=2329 [80577.434016] usb 2-1.1: New USB device strings: Mfr=1, Product=2, SerialNumber=5 [80577.434020] usb 2-1.1: […]

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Ask English Speaking

Passive voice (?) without ‘be’

I know that question was already asked on this site, but I’m not sure in the answer I read about. So, the question is could passive voice exist without the verb ‘be’? Here are examples: Mission is accomplished. The usual “mission accomplished” message. In the first case, we have a passive voice. In second, I […]

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Mastering Development User Help

FortiClient SSLVPN Configuration

I would like to setup VPN connection using mentioned software on Ubuntu 18.04.4 LTS. Binary source: SOURCE. The application is 32 bit while operating system is 64 bit, after installing some libraries app run. I have found that app doesn’t recognize domain names, so I use numbers. After clicking Connect, I receive Notice: Insufficient credential(s). […]

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Ask Mathematics

Exercise 3.5.7 of Tao’s Analysis I: A question about direct sums.

Exercise 3.5.7 in Tao’s Analysis I reads as follows: Let $X,Y$ be sets, and let $\pi_{X\times Y\to X}: X \times Y \to X$ and $\pi_{X\times Y\to Y}: X \times Y \to Y$ be the maps $\pi_{X\times Y\to X}(x,y):=x$ and $\pi_{X\times Y\to Y}(x,y):=y$; these maps are known as the co-ordinate functions on $X \times Y$. Show […]

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Development Linux

Where is the `–` (double dash) argument documented?

There are some utilities that accept a — (double dash) as the signal for “end of options”, required when a file name starts with a dash: $ echo “Hello World!” >-file $ cat — -file Hello World! $ cat -file # cat – -file fails in the same way. cat: invalid option — ‘f’ Try […]

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Development Linux

Where is the `–` (double dash) argument documented?

There are some utilities that accept a — (double dash) as the signal for “end of options”, required when a file name start with a dash: $ echo “Hello World!” >-file $ cat — -file # cat – -file fails in the same way. Hello World! $ cat -file cat: invalid option — ‘f’ Try […]

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Development

Delete Laravel file from storage/app/public/photos

I am trying to delete a file from storage/app/public/photos. The url that I am getting from the front end is http/MY_IP/app_name/public/storage/photos/file_name. I tried both unlink and File:delete, but doesn’t work because, I believe, filepath is not proper. I tried basename and public_path but it doesn’t solve it. Any help? $file_path = public_path(basename($photoToDelete)); if(File::exists($file_path)) File::delete($file_path); Edit: […]

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Development

Node redis ETIMEOUT issue

I’ve been using node-redis for a while and so far so good. However, upon setting up a new environment, I had a typo on the hostname (or password) and it wouldn’t connect. But because this was an already working application I developed some time ago, it was kind of hard to track the actual issue. […]