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NFS - Network File System
When a file that is open on an NFS disk is unlinked (rm'd), a file .nfsXXXX is created. When the file is closed, the tmp file is removed. If the client crashes first, you may find these little NFS turds lying around.
unix  network  filesystem  nfs  turd  explained 
yesterday by kme
What is the difference between "expose" and "publish" in Docker? - Stack Overflow
PS: If you do -p, but do not EXPOSE, Docker does an implicit EXPOSE. This is because if a port is open to the public, it is automatically also open to other Docker containers. Hence -p includes EXPOSE. That's why I didn't list it above as a fourth case.
docker  networking  config  explained 
2 days ago by kme
bash - How to escape history expansion exclamation mark ! inside a double quoted string? - Stack Overflow
In your last example,
<code class="language-bash">echo "$(echo '!b')"</code>

the exclamation point is not single-quoted. Because history expansion occurs so early in the parsing process, the single quotes are just part of the double-quoted string; the parser hasn't recognized the command substitution yet to establish a new context where the single quotes would be quoting operators.

To fix, you'll have to temporarily turn off history expansion:
<code class="language-bash">set +H
echo "$(echo '!b')"
set -H
bash  historyexpansion  shell  options  annoyance  solution  explained 
7 days ago by kme
PHP: Installation - Manual
PHP is glue. It is the glue used to build cool web applications by sticking dozens of 3rd-party libraries together and making it all appear as one coherent entity through an intuitive and easy to learn language interface. The flexibility and power of PHP relies on the stability and robustness of the underlying platform. It needs a working OS, a working web server and working 3rd-party libraries to glue together. When any of these stop working PHP needs ways to identify the problems and fix them quickly. When you make the underlying framework more complex by not having completely separate execution threads, completely separate memory segments and a strong sandbox for each request to play in, further weaknesses are introduced into PHP's system.

If you want to use a threaded MPM, look at a FastCGI configuration where PHP is running in its own memory space.
php  apache  mpm_prefork  mpm_worker  mpm_event  webmaster  explained  solution 
11 days ago by kme
Top to down, left to right (Surprise talk) - James Powell - YouTube
'global' and 'nonlocal' explained (Python statements which do not produce any executable bytecode)
python  internals  compilation  bytecode  scope  explained  conferencetalk  video 
14 days ago by kme
Variables in GNU Make recipes, is that possible? - Super User
This doesn't work because the make tool starts a new shell process for each recipe line. And shell variables – even 'exported' environment variables – cannot possibly propagate "upwards"; they're gone as soon as the shell process exits.

The traditional method is to join the recipe lines using \ in the Makefile:
<code class="language-make">foo: bar baz
line1; \
line2; \
make  makefiles  variables  recipes  explained  newbie 
4 weeks ago by kme
fc - "fix command"
In the KornShell, the alias r (``re-do") is preset to fc -e - (equivalent to the POSIX fc -s). This is probably an easier command name to remember than fc (``fix command"), but it does not meet the Utility Syntax Guidelines. Renaming fc to hist or redo was considered, but since this description closely matches historical KornShell practice already, such a renaming was seen as gratuitous. Users are free to create aliases whenever odd historical names such as fc, awk, cat, grep, or yacc are standardized by POSIX.
fc  history  unix  posix  butwhy  explained 
6 weeks ago by kme
html - Howto: div with onclick inside another div with onclick javascript - Stack Overflow
Basically there are two event models in javascript. Event capturing and Event bubbling. In event bubbling, if you click on inside div, the inside div click event fired first and then the outer div click fired. while in event capturing, first the outer div event fired and than the inner div event fired. To stop event propagation, use this code in your click method.

<code class="language-javascript">if (!e) var e = window.event;
e.cancelBubble = true;
if (e.stopPropagation) e.stopPropagation();</code>
webdevel  javascript  eventhandling  capture  bubbling  explained 
6 weeks ago by kme
Why did reCAPTCHA get replaced with a clickbox (noCAPTCHA)? - Quora
Secondly, Google (or websites) now have enough personally identifying biometric and other data about internet users that the following CAPTCHA alternative is feasible, via Are you a robot? Introducing “No CAPTCHA reCAPTCHA”:
Last year we developed an Advanced Risk Analysis backend for reCAPTCHA that actively considers a user’s entire engagement with the CAPTCHA—before, during, and after—to determine whether that user is a human. This enables us to rely less on typing distorted text and, in turn, offer a better experience for users. In cases when the risk analysis engine can't confidently predict whether a user is a human or an abusive agent, it will prompt a CAPTCHA to elicit more cues, increasing the number of security checkpoints to confirm the user is valid.
webdevel  recaptcha  biometric  security  fingerprinting  explained 
7 weeks ago by kme
What are ported and unported Licence (CC) | OER Africa
Unported licences are licences that are not associated with any specific jurisdiction (e.g. country). They do not mention any particular jurisdiction’s law.
cc  creativecommons  license  explained 
8 weeks ago by kme
The Complete Guide to PowerShell Punctuation - Simple Talk
Backtick is backslash, basically, including for line continuation. Bad choice if you ask me, because it's not visually distinctive enough. It looks like crumbs in your code.
powershell  windows  shellscripting  syntax  grammar  explained  reference  newbie 
january 2020 by kme
Difference between "Command substitution" and "Process substitution"
It's just a shame the first reply is "I do not know what you mean by 'process substitution'". Like, look it up and learn something, bro.

Also a shame that no one mentions it's Korn- and Bash-specific, although zsh probably has it, too.
unix  bash  korn  shell  shellscripting  processsubstitution  thisvsthat  commandsubstitution  newbie  explained 
december 2019 by kme
So I just watched Snoop Dogg dropping some knowledge on my daughter : sysadmin
My daughter is watching a Netflix show called Storybots, and the question on this episode is how a computer works. Of course, the Storybots go inside and meet the OS, which happens to be Snoop Dog himself. I think he did a great job explaining the CPU, bus, storage, and how the machine processes requests. I'm impressed. And his dance at the end after serving up the human's request for a cat picture lol.
computers  explained 
november 2019 by kme
What the heck are you actually using NoSQL for? - High Scalability -
Has an impressive list of references at the bottom, for further reading.
API limiting. This is a great fit for Redis as a rate limiting check needs to be made for every single API hit, which involves both reading and writing short-lived data.
webdevel  devel  database  dba  architecture  nosql  explained  butwhy  forethereferences 
november 2019 by kme
I’m begging you: Stop donating canned goods to food banks | National Post
Canned goods have a particularly low rate of charitable return. They’re heavy, they’re awkward and they can be extremely difficult to fit into a family’s meal plan. Worst of all, the average consumer is buying their canned goods at four to five times the rock-bottom bulk price that can be obtained by the food bank itself.

That $1 you spent on tuna could have purchased $4 worth of tuna if put in the hands of non-profit employee whose only job is to buy food as cheaply as possible. The savvy buyers at the Calgary Food Bank, for instance, promise that they can stretch $1 into $5.
donations  charity  effectivealtruism  explained  video 
october 2019 by kme
string - What is the difference between UTF-32 and UCS-4? - Stack Overflow
UTF-32 has started as a subset of UCS-4. Now it is identical except that the UTF-32 standard has additional Unicode semantics. See details on wikipedia:

However, I am not exactly sure, what additional Unicode semantics means. Maybe someone can provide a better answer.
unicode  widecharacters  ucs4  explained 
september 2019 by kme
newlines - What's the point in adding a new line to the end of a file? - Unix & Linux Stack Exchange
Example: the output of GNU sort always ends with a newline. So if the file foo is missing its final newline, you'll find that sort foo | wc -c reports one more character than cat foo | wc -c.

Not necessarily the reason, but a practical consequence of files not ending with a new line:

Consider what would happen if you wanted to process several files using cat. For instance, if you wanted to find the word foo at the start of the line across 3 files:
<code class="language-bash">cat file1 file2 file3 | grep -e '^foo'</code>
newlineterminator  unix  textfiles  textprocessing  explained 
july 2019 by kme
Jafrog's dev blog
\x1b[0m - "reset"
To list all colors available in 256 color mode with their codes run
<code class="language-bash">
for code in {0..255}
do echo -e "\e[38;5;${code}m"'\\e[38;5;'"$code"m"\e[0m"
cli  commandline  ansicolors  reference  explained 
july 2019 by kme
Practical AI #1: Meet Practical AI hosts Daniel Whitenack and Chris Benson |> News and podcasts for developers |> Changelog
Yeah, definitely. It’s just super-awesome to be here with you guys. Like you mentioned, Adam, we’ve been talking about this for quite a while, so…
ai  ml  deeplearning  explained 
june 2019 by kme
Want a New Emoji? Good Luck. - by Andy Warner
How a nearly invisible cabal of tech industry leaders controls what you can and can’t type 🤔
emoji  unicode  language  journalism  cabals  cartoon  webcomic  explained 
june 2019 by kme
GitHub - alex/what-happens-when: An attempt to answer the age old interview question "What happens when you type into your browser and press enter?"
An attempt to answer the age old interview question "What happens when you type into your browser and press enter?" - alex/what-happens-when
interviewquestions  tech  explained 
june 2019 by kme
history - Why is the xargs -i option deprecated? - Unix & Linux Stack Exchange |
This makes me feel old, because I remember when 'xargs' *only* had '-i' and '-l', and this change feels completely arbitrary to me.
The -l and -i options appear in the 1997 version of the POSIX standard, but do not appear in the 2004 version of the standard. Therefore you should use -L and -I instead, respectively.
xargs  unix  shellscripting  posix  explained  solution 
march 2019 by kme
MacBook Air (2018) review: Testing the 1.6GHz dual-core Core i5 laptop | Macworld
One of the things we loved about the MacBook Air was the MagSafe charging connector. USB-C charging is convenient in a “you only need one cord” sort of way, but there is almost no old-school Mac laptop user that doesn’t have a dozen stories about how the magnetic breakaway charger saved it from certain doom when someone tripped over the power cord.
macbook  air  review  apple  mac  hardware  explained 
march 2019 by kme
The New MacBook Air Has a Looming Reliability Issue
The MacBook Air is held in high regard for being a well-built laptop that lasts forever. And since the Air has lasted so long, many users (including most of my relatives) have held onto their older models. These systems still work, but they’re finally starting to show their age, leaving their owners looking for a new laptop.
macbook  air  mac  hardware  keyboard  review  explained 
march 2019 by kme
The #! magic, details about the shebang/hash-bang mechanism |
what's special about #!

#! was a great hack to make scripts look and feel like real executable binaries.

But, as a little summary, what's special about #!? (list mostly courtesy of David Korn)

- the interpretername must not contain blanks
- the length of the #! is much smaller than the maximum path length
- $PATH is not searched for the interpreter
- (apart from an absolute path, the #! line also accepts a relative path,
- and #!interpreter is equivalent to #!./interpreter,
- however, it's not of any practical use)
- the interpreter usually must no be a #! script again
- the handling of arguments in the #! line itself is varying
- the setuid mechanism may or may not be available for the script
- there's no way to express #!$SHELL

And why shebang? In music, '#' means sharp. So just shorten #! to sharp-bang. Or it might be derived from "shell bang". All this probably under the influence of the american slang idiom "the whole shebang" (everything, the works, everything involved in what is under consideration). See also the wiktionary, jargon dictionary or Merriam-Websters. Sometimes it's also called hash-bang, pound-bang, sha-bang/shabang, hash-exclam, or hash-pling (british, isn't it?).

According to Dennis M. Ritchie (email answer to Alex North-Keys) it seems it had no name originally.
And Doug McIllroy mentioned (TUHS mailing list), that the slang for # at Bell Labs most probably was "sharp" at the time.
bourne  bash  posix  shell  shebang  unix  linux  shellscripting  history  butwhy  explained 
february 2019 by kme
bash - Set and Shopt - Why Two? - Unix & Linux Stack Exchange |
The difference is in the changed environment variable used by bash. Setting with the set command results in $SHELLOPTS. Setting with the shopt command results in $BASHOPTS.
bourne  bash  shell  configfile  configuration  history  butwhy  explained 
february 2019 by kme
Primary Cells Versus Cell Lines – ScienCell Research Laboratories |
Cell culture studies provide a valuable complement to in vivo experiments, allowing for a more controlled manipulation of cellular functions and processes. For decades, cell lines have played a critical role in scientific advancements, yet researchers have become increasingly cautious when interpreting data generated from cell lines only. Factors such as misidentified and contaminated cell lines have spurred renewed interest in primary cells [1,2]. Many researchers have chosen to work with cells lines as they are generally highly proliferative, and easier to culture and transfect. Most cell lines have been in culture for decades and are well adapted to the two-dimensional culture environment, and as a result, often differ genetically and phenotypically from their tissue origin and show altered morphology [3,4]. In contrast to cell lines, primary cells which are isolated directly from tissues, have a finite lifespan and limited expansion capacity. On the positive side, primary cells have normal cell morphology and maintain many of the important markers and functions seen in vivo [3,4]. Endothelial cell lines, for example, lack various functional markers, while primary endothelial cells retain these critical features.
cellline  primarycells  biology  wetlab  explained 
january 2019 by kme
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