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kme : thisvsthat   56

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 
9 weeks ago by kme
git - Why should I care about lightweight vs. annotated tags? - Stack Overflow
@Chris yes, as the answer says, "The big plus of an annotated tag is that you know who created it." You can always try things yourself to find out: git tag -a -m 'my message' my-tag; git show my-tag – Cascabel Aug 9 '17 at 16:17


Note, though, that '-a' is implied when '-m' is given.
git  tags  annotatedtags  thisvsthat  lightweighttags  release  solution 
june 2019 by kme
A year on — our experience launching a paid, proprietary product on Linux. | https://blog.hiri.com/
Unsurprisingly, security is a major concern for Linux users. Thankfully, we learned this lesson early after watching several of our competitors getting roasted online for laissez-faire data collection. In many ways, we are lucky that our product is secure by design (we don’t store or process data online — strictly between you and your mail server). None the less, we are very open with users regarding the data we collect, and users can turn off what little data collection we do. Of course, the boundaries are much clearer now thanks to GDPR. Startups are less likely to make privacy related blunders. But if you are creating a product, think twice about using 3rd party services.


Interesting...
The most surprising and delightful aspect of this journey has been the feedback from Linux users. To put it mildly, they care about software. Many of them are software developers themselves. We call it professional sympathy! Their generosity, quality insights and willingness to help us squash bugs have accelerated the pace of our development and learning dramatically. So much so, that if I ever end up building another product, I’ll be going Linux first.
paidsoftware  thisvsthat  nonfree  linux  lessonslearned  email  client  alternativeto  exchange 
december 2018 by kme
What are your thoughts on sigils? : perl | https://www.reddit.com/
Larry Wall notes in an interview that «On a syntactic level, in the particular case of Perl, I placed variable names in a separate namespace from reserved words. That's one of the reasons there are funny characters on the front of variable names -- dollar signs and so forth. That allowed me to add new reserved words without breaking old programs.». Furthermore, first order lists allow for cleaner code sometimes. So I think sigils are great, but naturally inexperienced people often complain that they add clutter or make the code "unreadable" or "messy".

And I find that sigils give my code more visual rhythm and makes it easier to read


This, right here.

I don't need a fancy IDE or somehow encoding the type of the thing into the name of the thing to know what it is. Or, at least, the type of thing that the author wanted the interpreter to treat it as.

Having spent the last couple years in node/javascript land, too often it's a "oh, shit, it's a function?" is too common.
perl  language  design  perl5  syntax  thisvsthat  forthecomments  sigils 
september 2018 by kme
mysql - Differences between "Unique Key" and "Primary Key" - Database Administrators Stack Exchange | https://dba.stackexchange.com/
A table can have at most one PRIMARY KEY constraint but it can have as many as you want UNIQUE KEY constraints.

Columns that are part of the PRIMARY KEY must be defined as NOT NULL. That is not required for columns that are part of UNIQUE KEY constraints. If the columns are not Nullable, then there is no difference between Unique and Primary Keys.

Another minor difference is that you can choose the name you want for a UNIQUE KEY constraint (and index). On the other hand, the PRIMARY KEY has the default name: PRIMARY.

Also helpful:

Most important difference is in their purpose.

* Primary Key: Purpose of Primary Key is to act as a “KEY”. A primary key is a key in a relational database used to identify records.
* Unique Index: Unique Index is an “INDEX” intended for performance. Optimizer knows that for a condition "where x =:x” there will be only one record as a result – so it can prepare a plan suitable for that.
* Unique Constraint: It is a “CONSTRAINT” which makes sure that there are no duplicate values in that column. It is a constraint for data integrity.

Apart from their purpose, following points are noteworthy.

* Unless otherwise specified PRIMARY KEY will try to create a CLUSTERED INDEX (This point is about SQL Server though, as mentioned in the comment)
* There can be only one PRIMARY KEY per table; but there can be many unique constraints and unique indexes
* PRIMARY KEY is always not null but columns with unique constraint can hold NULL values
dba  primarykey  database  mysql  sql  thisvsthat  newbie  answered 
march 2018 by kme
html - Testing text() nodes vs string values in XPath - Stack Overflow | https://stackoverflow.com/
XPath text() = is different than XPath . =

(Matching text nodes is different than matching string values)

The following XPaths are not the same...
<code class="language-xpath">//span[text() = 'Office Hours']</code>

Says: Select the span elements that have an immediate child text node equal to 'Office Hours`.

[whereas]
<code class="language-xpath">//span[. = 'Office Hours']</code>

Says: Select the span elements whose string value is equal to 'Office Hours`.
xpath  xml  syntax  textcontent  thisvsthat  patternmatching  newbie  webdevel  reference  explained 
february 2018 by kme
Jorgen’s Weblog: Why systemd?
This is a really excellent explanation of why SysV init sucks, and the author even admits he's not a fan of systemd.
systemd  init  initsystem  unix  linux  thisvsthat  explained 
august 2017 by kme
TOML vs. JSON - Tom Limoncelli's EverythingSysadmin Blog
The other difference is around comments. One camp permits them and another camp doesn't. In operations often we need to be able to temporarily comment out a few lines, or include ad hoc messages. Operations people communicate by leaving breadcrumbs and todo items in files. Rather than commenting out some lines I could delete them and use version control to bring them back, but that is much more work. Also, often I write code in comments for the future. For example, as part of preparation for a recent upgrade, we added the future configuration lines to a file but commented them out. By including them, they could be proofread by coworkers.
toml  json  configuration  operations  sysadmin  breadcrumbs  documentation  butwhy  thisvsthat 
april 2017 by kme

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