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Git revert vs reset last N commits

Resetting, Checking Out & Reverting | Atlassian Git Tutorial is a nice guide about ways to undo some of the commits. Reset is a harder way to undo stuff that sometimes leaves no traces, Revert is a way to create a commit that undoes the last N commits, so history is preserved and that’s good.

A way to revert the last N commits is this: ¹

git revert --no-commit HEAD~3..

Two dots at the end are significant:

@cardamom Those specify a range. HEAD~3.. is the same as HEAD~3..HEAD

A saga about timezones

So. I wanted to change time back to Berlin time from Ukrainian time.

Something was wrong.

~ → timedatectl status
                      Local time: Fr 2020-08-28 18:50:55 EEST
                  Universal time: Fr 2020-08-28 15:50:55 UTC
                        RTC time: Fr 2020-08-28 15:50:55
                       Time zone: Europe/Berlin (EEST, +0300)
       System clock synchronized: yes
systemd-timesyncd.service active: yes
                 RTC in local TZ: no

UTC is right, time zone is right, but local time is wrong.

Then I google and see that Europe/Berlin is actually EEST, +0200!

Then I realize the following:

Last time I needed to change the time, I changed the timezone, by doing:

sudo cp /usr/share/zoneinfo/Europe/Kiev /etc/localtime

(#Kyivnotkiev)

/etc/localtime was a SYMBOLIC LINK to /usr/share/zoneinfo/Europe/Berlin

~ → file /etc/localtime
/etc/localtime: symbolic link to ../usr/share/zoneinfo/Europe/Berlin

By doing that, I rewrote the Berlin timezone by making it Kyiv, changing the time on my computer and changing the Berlin timezone itself.

Fixed this with a bandaid by making my timezone Europe/Rome, as /usr/share/zoneinfo/Europe/Rome was never overwritten.

↑130 ~ → timedatectl status
                      Local time: Fr 2020-08-28 17:59:15 CEST
                  Universal time: Fr 2020-08-28 15:59:15 UTC
                        RTC time: Fr 2020-08-28 15:59:15
                       Time zone: Europe/Rome (CEST, +0200)
       System clock synchronized: yes
systemd-timesyncd.service active: yes
                 RTC in local TZ: no

Happy end.

VPN DNS issues

Seemed to have a conflict w/ IPv6 VPN vs the IPv4 one, first had priority. Then I had an issue where the VPN IP was the same as the IP of my router. Fixed by moving router IP. Learned a lot about how DNS works.

Lookup website using particular DNS

• nslookup somewebsite.com 8.8.8.8 looks up the website using the provided 8.8.8.8 DNS server.
• systemd-resolve --status gives the current DNS settings.
• sudo systemd-resolve --flush-caches flushes the DNS caches.

git diff with full context

How to get git diff with full context? - Stack Overflow - git diff -U1000000 - or wc -l in place of the number - any number of line larger than the file works.

Intellij idea test results CLI output w/ ideavim

The window w/ CLI output or test output can be happily manipulated with ideavim! Now I can copypaste everything easily!

Jupyter Notebook vim mode

When operating on cells, not text (= not insert mode), the usual j/k commands select cells when shift is used (J/K). This is neat. I should read the documentation.

Java brackets in for statements

If you have only one statement in for loops, you can drop the brackets:

for (final String dt: distanceTypes)
    for (final double co : cutoffs)
        your_one_statement();

That said, it’s not a good idea :) Answer has details about the definitions, default scope for for is next statement. A statement can have brackets.

for loop without braces in java - Stack Overflow

Ideas / TODO / Fiamma / PKM

Possibly sometime rewrite my link wiki (pchr8.net/f/)’s bookmarking userscript to accept data as title/complexity/rating/tag1 two three/Cat1 cat2 cat3 instead of the current multiline thingy, might be even easier to fit it into a userprompt

Random / interesting

• Chicago goes into lockdown as bridges raised and freeway exits closed to restrict access to downtown | Daily Mail Online

Jaro-winkler similarity for empty strings (#nlp)

Jaro-Winkler handling empty strings · Issue #28 · tdebatty/java-string-similarity - TL;DR officially ‘undefined’, what has to be returned in implementations depends on why you need it. These are nice edge cases I have to learn to watch for.

String similarity algo explained

String simularity has a nice table with similarity algos and how they perform with different changes.

{:height=“500px”}.

Git diff

Is much more flexible than expected. git diff --unified=0 doesn’t show the context lines, only the changed ones; in general the documentation is worth reading, could be a good tool to add to my belt for various one-off tasks.

pandas convert entire dataframe to str / value type

df.applymap(str) converts everythnig to str. df.applymap() applies a function to a Dataframe elementwise. (TODO anki)

pandas import numpy

If I don’t want to do import numpy as np separately (for things like np.nan), pd.np.nan works! ¹

pandas remove NaN/nan in str

np.nan in the dataframe can be removed w/ df.fillna(''), but after getting converted to string the NaN become nan and have to be removed by the string operation. As a string operation, it’s important to watch out for strings containing nans, for example:

pd.DataFrame({'one':['two','three','four',pd.np.nan,23,'nonanme']}).applymap(str).replace('nan','',regex=True) would change the last element. All answers here seem to have this issue.

So to remove them from a string representation, pd.DataFrame({'one':['two','three','four',pd.np.nan,23,'nonanme']}).applymap(str).replace('^nan$','',regex=True) works, with a regex for nan.

qutebrowser leave passthrough mode

Changed keybinding to config.bind('<Ctrl-Shift-+>', 'leave-mode', mode='passthrough'), which translates to <C-S-=>, but it seems to see = as + because Shift is being pressed.

Diff character-level differences highlights

command line - Using ‘diff’ (or anything else) to get character-level diff between text files - Stack Overflow gives this one nice string: git diff --word-diff=color --word-diff-regex=. file1 file2 which gives red/green characters for deletions/additions. Also, chaining greps also works nicely with grep -o which passes only the text of the actual match. Grep doesn’t support capturing groups.

Intellij idea CheckStyle plugin

CheckStyle-IDEA - plugin for IntelliJ IDEA and Android Studio | JetBrains exists and I had better luck w/ it than with importing the checkstyle file from Style in Settings. Gives highlights inside the code itself automatically.

Intellij idea - “Add comment” style - put them before the text, not at first column

• Can be set in “Code generation”: Action gets used w/ Ideavim’s gcc etc.

To configure settings for where the generated line or block comments should be placed in Java, in the Settings/Preferences dialog Ctrl+Alt+S, go to Editor | Code Style | Java and on the Code Generation tab use options in the Comment Code section. ¹

Intellij Idea Checkstyle highlights

Intellij Idea Checkstyle highlights seem to refresh when I change a character and similar edits, but not when I change indentation w/ IdeaVim.

Intellij idea Rainbow CSV plugin

Rainbow CSV plugin is nice and highlights columns of the CSV in different colours - something I didn’t know I needed.

Checkstyle documentation

checkstyle – Imports explains (“Rationale:”) the rules used and in general is quite well-written.

Checkstyle equalsavoidnull

"My_Sweet_String".equals(nullString); is the way to go for string comparisons apparently, it avoids potential nullPointerExceptions. ²

String similarity algorithms in Java

tdebatty/java-string-similarity: Implementation of various string similarity and distance algorithms: Levenshtein, Jaro-winkler, n-Gram, Q-Gram, Jaccard index, Longest Common Subsequence edit distance, cosine similarity … is awesome.

A library implementing different string similarity and distance measures. A dozen of algorithms (including Levenshtein edit distance and sibblings, Jaro-Winkler, Longest Common Subsequence, cosine similarity etc.) are currently implemented.

String similarity / string distances normalization #nlp

algorithm - Normalizing the edit distance - Stack Overflow has info about normalizing distances like Levenshtein etc. And how a normalized distance is not a metric anymore, as it violates the Triangle inequality w/ sum of two sides of the triangle not being longer than the third.

Longest common subsequence

Longest common subsequence problem - Wikipedia is different from Longest Common Substring is that subsequences are not required to be uninterrupted.

Random / Interesting

!Bernard Moitessier’s tomb is Bernard Moitessier’s tomb.

Intellij idea source code navigation

• ` to navigate to last edited location

… though most of this is helpfully configurable in ideavim; esp: map <leader>b :action GotoDeclaration<CR>¹ for “go to declaration”, which is <Alt+B> in vanilla ideavim. I should track things I use my mouse for most often and replace them with ideavim shortcuts.

Lenovo Thinkpad disable Fn key

Nice that I don’t have to use BIOS for this. <Fn+Esc> disables Fn key functionality.

Random / books / to read

• Black on Red: My 44 Years Inside the Soviet Union: An Autobiography by Robert Robinson | Goodreads - recommended by A.

I read Black On Red: My 44 Years Inside The Soviet Union, a book by Robert Robinson, An African-American who lived in Detroit during the Depression. I had to read it again, for it is about as gripping an autobiography as one can find.

• Russian political jokes - Wikipedia

Mediawiki change allowed filetypes

$wgFileExtensions = [
    'png', 'gif', 'jpg', 'jpeg', 
];