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@MiguelArgentina
Last active September 4, 2023 18:12
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Annotations that can be handy on a daily basis

Heroku related

Heroku log tails:

  • heroku logs --app app-name --tail
  • heroku logs --app app-name -n 1500 (for the last 1500 lines)
  • heroku logs --app app-name --tail --ps worker (worker logs)

Heroku DB dump:

  • heroku pg:backups:capture -a app-name (create the dump)
  • heroku pg:backups:download -a app-name (download the dump)
  • pg_restore --clean -U user_name -d db_name "path/to/file name.dump"

Heroku check DB backups and download them:

  • heroku pg:backups --app app-name output:
ID    Created at                 Status                               Size     Database
────  ─────────────────────────  ───────────────────────────────────  ───────  ────────
b059  2023-07-30 23:41:19 +0000  Completed 2023-07-30 23:41:25 +0000  33.11MB  MAROON
b058  2023-07-30 02:43:34 +0000  Completed 2023-07-30 02:43:40 +0000  32.94MB  MAROON
b057  2023-07-29 23:31:25 +0000  Completed 2023-07-29 23:31:31 +0000  32.93MB  MAROON
b056  2023-07-28 19:47:22 +0000  Completed 2023-07-28 19:47:33 +0000  32.57MB  MAROON
b055  2023-07-28 18:32:13 +0000  Completed 2023-07-28 18:32:20 +0000  32.53MB  MAROON
b054  2023-07-25 23:41:59 +0000  Completed 2023-07-25 23:42:07 +0000  31.72MB  MAROON
b053  2023-07-24 18:31:40 +0000  Completed 2023-07-24 18:31:47 +0000  31.35MB  MAROON
  • heroku pg:backups:url url-id --app app-name

Reset the autoincrement value when

PG::UniqueViolation: ERROR:  duplicate key value violates unique constraint "table_pkey"
DETAIL:  Key (id)=(121006) already exists.
  1. Open psql on heroku:

    heroku psql -a app-name

  2. Make a call to nextval for that table:

    SQL SELECT nextval(PG_GET_SERIAL_SEQUENCE('"table"', 'id'));

  3. Get the value most recently obtained by nextval for this sequence in the current session along with the maximum value for id in table:

    SELECT
        CURRVAL(PG_GET_SERIAL_SEQUENCE('"table"', 'id')) AS "Current Value",
        MAX("id") AS "Max Value"
    FROM "table";
  4. Our sequence is out-of-sync when the Current Value is less than Max Value!!

  5. If our autoincrement value is out of sync we can use the below code. This will set the correct number for the next auto increment

    SELECT SETVAL(
        (SELECT PG_GET_SERIAL_SEQUENCE('"table"', 'id')),
        (SELECT (MAX("id") + 1) FROM "table"),
        FALSE);

Gist markdown examples

A collection of Markdown code and tricks that were tested to work in Gist.

This and all public gists in https://gist.github.com/ww9 are Public Domain. Do whatever you want with it including , no need to credit me.

Todo

Table of Contents

Headers Emphasis Lists Links Images Code and Syntax Highlighting Tables Blockquotes Inline HTML Horizontal Rule Line Breaks YouTube Videos TeX Mathematical Formulae

Task lists

- [x] Task 1
- [ ] Task 2
- [ ] Task 3

Result:

  • Task 1
  • Task 2
  • Task 3

Collapsible content (spoilers)

Details

Content between <details> and </details> is hidden. You need to escape HTML tags them.

print("hello world!")
# H1
## H2
### H3
#### H4
##### H5
###### H6

Alternatively, for H1 and H2, an underline-ish style:

Alt-H1
======

Alt-H2
------

H1

H2

H3

H4

H5
H6

Alternatively, for H1 and H2, an underline-ish style:

Alt-H1

Alt-H2

Emphasis, aka italics, with *asterisks* or _underscores_.

Strong emphasis, aka bold, with **asterisks** or __underscores__.

Combined emphasis with **asterisks and _underscores_**.

Strikethrough uses two tildes. ~~Scratch this.~~

Emphasis, aka italics, with asterisks or underscores.

Strong emphasis, aka bold, with asterisks or underscores.

Combined emphasis with asterisks and underscores.

Strikethrough uses two tildes. Scratch this.

1. First ordered list item
2. Another item
  * Unordered sub-list. 
1. Actual numbers don't matter, just that it's a number
  1. Ordered sub-list
4. And another item.  
   
   Some text that should be aligned with the above item.

* Unordered list can use asterisks
- Or minuses
+ Or pluses
  1. First ordered list item
  2. Another item
  • Unordered sub-list.
  1. Actual numbers don't matter, just that it's a number

  2. Ordered sub-list

  3. And another item.

    Some text that should be aligned with the above item.

  • Unordered list can use asterisks
  • Or minuses
  • Or pluses

There are two ways to create links.

[I'm an inline-style link](https://www.google.com)

[I'm a reference-style link][Arbitrary case-insensitive reference text]

[You can use numbers for reference-style link definitions][1]

Or leave it empty and use the [link text itself]

URLs and URLs in angle brackets will automatically get turned into links. 
http://www.example.com or <http://www.example.com> and sometimes 
example.com (but not on Github, for example).

Some text to show that the reference links can follow later.

[arbitrary case-insensitive reference text]: https://www.mozilla.org
[1]: http://slashdot.org
[link text itself]: http://www.reddit.com

I'm an inline-style link

I'm a reference-style link

You can use numbers for reference-style link definitions

Or leave it empty and use the link text itself

URLs and URLs in angle brackets will automatically get turned into links. http://www.example.com or http://www.example.com and sometimes example.com (but not on Github, for example).

Some text to show that the reference links can follow later.

Here's our logo (hover to see the title text):

Inline-style: 
![alt text](https://github.com/adam-p/markdown-here/raw/master/src/common/images/icon48.png "Logo Title Text 1")

Reference-style: 
![alt text][logo]

[logo]: https://github.com/adam-p/markdown-here/raw/master/src/common/images/icon48.png "Logo Title Text 2"

Here's our logo (hover to see the title text):

Inline-style: alt text

Reference-style: alt text

Code blocks are part of the Markdown spec, but syntax highlighting isn't. However, many renderers -- like Github's and Markdown Here -- support syntax highlighting. Markdown Here supports highlighting for dozens of languages (and not-really-languages, like diffs and HTTP headers); to see the complete list, and how to write the language names, see the highlight.js demo page.

Inline `code` has `back-ticks around` it.

Inline code has back-ticks around it.

Blocks of code are either fenced by lines with three back-ticks ```, or are indented with four spaces. I recommend only using the fenced code blocks -- they're easier and only they support syntax highlighting.

```javascript
var s = "JavaScript syntax highlighting";
alert(s);
```
 
```python
s = "Python syntax highlighting"
print s
```
 
```
No language indicated, so no syntax highlighting. 
But let's throw in a <b>tag</b>.
```
var s = "JavaScript syntax highlighting";
alert(s);
s = "Python syntax highlighting"
print s
No language indicated, so no syntax highlighting in Markdown Here (varies on Github). 
But let's throw in a <b>tag</b>.

Again, to see what languages are available for highlighting, and how to write those language names, see the highlight.js demo page.

Tables aren't part of the core Markdown spec, but they are part of GFM and Markdown Here supports them. They are an easy way of adding tables to your email -- a task that would otherwise require copy-pasting from another application.

Colons can be used to align columns.

| Tables        | Are           | Cool  |
| ------------- |:-------------:| -----:|
| col 3 is      | right-aligned | $1600 |
| col 2 is      | centered      |   $12 |
| zebra stripes | are neat      |    $1 |

The outer pipes (|) are optional, and you don't need to make the raw Markdown line up prettily. You can also use inline Markdown.

Markdown | Less | Pretty
--- | --- | ---
*Still* | `renders` | **nicely**
1 | 2 | 3

Colons can be used to align columns.

Tables Are Cool
col 3 is right-aligned $1600
col 2 is centered $12
zebra stripes are neat $1

The outer pipes (|) are optional, and you don't need to make the raw Markdown line up prettily. You can also use inline Markdown.

Markdown Less Pretty
Still renders nicely
1 2 3
> Blockquotes are very handy in email to emulate reply text.
> This line is part of the same quote.

Quote break.

> This is a very long line that will still be quoted properly when it wraps. Oh boy let's keep writing to make sure this is long enough to actually wrap for everyone. Oh, you can *put* **Markdown** into a blockquote. 

Blockquotes are very handy in email to emulate reply text. This line is part of the same quote.

Quote break.

This is a very long line that will still be quoted properly when it wraps. Oh boy let's keep writing to make sure this is long enough to actually wrap for everyone. Oh, you can put Markdown into a blockquote.

You can also use raw HTML in your Markdown, and it'll mostly work pretty well.

<dl>
  <dt>Definition list</dt>
  <dd>Is something people use sometimes.</dd>

  <dt>Markdown in HTML</dt>
  <dd>Does *not* work **very** well. Use HTML <em>tags</em>.</dd>
</dl>
Definition list
Is something people use sometimes.
Markdown in HTML
Does *not* work **very** well. Use HTML tags.
Three or more...

---

Hyphens

***

Asterisks

___

Underscores

Three or more...


Hyphens


Asterisks


Underscores

My basic recommendation for learning how line breaks work is to experiment and discover -- hit <Enter> once (i.e., insert one newline), then hit it twice (i.e., insert two newlines), see what happens. You'll soon learn to get what you want. "Markdown Toggle" is your friend.

Here are some things to try out:

Here's a line for us to start with.

This line is separated from the one above by two newlines, so it will be a *separate paragraph*.

This line is also a separate paragraph, but...
This line is only separated by a single newline, so it's a separate line in the *same paragraph*.

Here's a line for us to start with.

This line is separated from the one above by two newlines, so it will be a separate paragraph.

This line is also begins a separate paragraph, but...
This line is only separated by a single newline, so it's a separate line in the same paragraph.

(Technical note: Markdown Here uses GFM line breaks, so there's no need to use MD's two-space line breaks.)

They can't be added directly but you can add an image with a link to the video like this:

<a href="http://www.youtube.com/watch?feature=player_embedded&v=YOUTUBE_VIDEO_ID_HERE
" target="_blank"><img src="http://img.youtube.com/vi/YOUTUBE_VIDEO_ID_HERE/0.jpg" 
alt="IMAGE ALT TEXT HERE" width="240" height="180" border="10" /></a>

Or, in pure Markdown, but losing the image sizing and border:

[![IMAGE ALT TEXT HERE](http://img.youtube.com/vi/YOUTUBE_VIDEO_ID_HERE/0.jpg)](http://www.youtube.com/watch?v=YOUTUBE_VIDEO_ID_HERE)

A full description of TeX math symbols is beyond the scope of this cheatsheet. Here's a good reference, and you can try stuff out on CodeCogs. You can also play with formulae in the Markdown Here options page.

Here are some examples to try out:

$-b \pm \sqrt{b^2 - 4ac} \over 2a$
$x = a_0 + \frac{1}{a_1 + \frac{1}{a_2 + \frac{1}{a_3 + a_4}}}$
$\forall x \in X, \quad \exists y \leq \epsilon$

The beginning and ending dollar signs ($) are the delimiters for the TeX markup.

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