421 karma · joined September 6, 2017
...except at the poles! (There the sun will appear to be moving along the horizon, and there is no day/night in the usual sense.)
And when you take the pedantry into account (top vs centre of sun, refraction) the length of the day/night is no longer the same around the globe, since the effect in terms of time is different at different latitudes.
It just requires you to be the owner of the file (https://serverfault.com/a/337810), no special permissions. On the other hand, editing the ctime is not easy -- it requires tricks (e.g. change the computer clock, which typically requires root privileges).
Linux also has a ctime ("status change time"), which is automatically updated when the content or metadata (inode) are changed. It is not possible to change from userspace (you have to use tricks such as changing the computer clock or directly modifying the disk). This gives you the security benefits, but it is not commonly used e.g. in backup tools, precisely because they want to be able to set "fake" timestamps.
If you don't mind saving the file to disk, you can do:
sqlite3 -newline '' ':memory:' "SELECT data FROM zipfile('eurofxref-hist.zip')" \
| sqlite3 -csv ':memory:' '.import /dev/stdin stdin' \
"select ...;"
curl -s https://www.ecb.europa.eu/stats/eurofxref/eurofxref-hist.zip \
| { printf "SELECT data FROM zipfile(x'"; xxd -p | tr -d '\n'; printf "')"; } \
| sqlite3 -newline '' \
| sqlite3 -csv ':memory:' '.import /dev/stdin stdin' \
"select ...;"> Files created by zip can be uncompressed by gzip only if they have a single member compressed with the “deflation” method. This feature is only intended to help conversion of tar.zip files to the tar.gz format.
-- https://www.gnu.org/software/gzip/manual/html_node/Overview....
> Uber Sheets
Hee hee, this name is funny on a number of levels :)
There isn't a simple and fast way to find parent objects, but here is a slow hack:
git_find_references() {
if [ "$#" -ne 1 ] || [ "${1#-}" != "$1" ]; then
echo "usage: git_find_references <HASH>" >&2; return 1
fi
local target="$1"
git cat-file --batch-check --batch-all-objects --unordered |
while read -r hash type size; do
if [ "$type" != "blob" ] && git cat-file -p "$hash" | grep -F -q "$target"; then
printf "%s %s\n" "$hash" "$type"
fi
done
}
# example:
git_find_references 1cae71a9d5b24991c0d632b45186ca8a250e5d52
Note that this function will be very slow on large repositories. I can't think of a way to make it faster without writing actual code. (My only tip is that you can search for multiple targets at once by changing the grep command to `grep -E -q "$target"` and then using `git_find_references "HASH1|HASH2|HASH3"`.)
Once you find the referring objects, you can use `git cat-file -p <hash>` on them to see their content, and you can repeatedly invoke this function to walk up a directory tree until you get to the enclosing commit.
---
To actually fix the corruption, you have a couple of options:
- If the corruption is in a branch that you don't care about, just delete the branch.
- Find a good copy of the object, e.g. from another repository (you said the object did not appear, but I just want to point out that you should check using `git cat-file -p <hash>` rather than by looking in .git/objects/, because objects can also be stored in packs). Or you might be able to work out what the content was (if the corrupt object is a blob, aka file, you might be able to work out the content based on the previous and next versions of that file; `git hash-object <file>` will tell you if it's exactly right, but won't give you any hints if it's slightly wrong).
- Rewrite the history to remove/replace the corrupt object. You can use a tool such as `git-filter-repo` (docs: https://htmlpreview.github.io/?https://github.com/newren/git..., in particular see --strip-blobs-with-ids). You can also use `git replace` to temporarily replace the corrupt object with a placeholder; it won't fix the commit history, but it might be useful if the corruption causes commands to fail.
The idea is to balance a scale with the crown on one side and an equal mass of gold on the other side (no water yet), and then submerge the entire scale in water. Now there will still be the same mass on each side, but there will additionally be a buoyancy force on each side proportional to its volume. So if the volume of the crown is different from the volume of the reference gold, the buoyancy forces will be different and the scale will tip.
> The story of the golden crown does not appear anywhere in Archimedes' known works. The practicality of the method described has been called into question due to the extreme accuracy that would be required to measure water displacement. Archimedes may have instead sought a solution that applied the hydrostatics principle known as Archimedes' principle, found in his treatise On Floating Bodies: a body immersed in a fluid experiences a buoyant force equal to the weight of the fluid it displaces.[34] Using this principle, it would have been possible to compare the density of the crown to that of pure gold by balancing it on a scale with a pure gold reference sample of the same weight, then immersing the apparatus in water. The difference in density between the two samples would cause the scale to tip accordingly.[12] Galileo Galilei, who invented a hydrostatic balance in 1586 inspired by Archimedes' work, considered it "probable that this method is the same that Archimedes followed, since, besides being very accurate, it is based on demonstrations found by Archimedes himself."
-- https://en.wikipedia.org/wiki/Archimedes#Archimedes'_princip...
To clarify, the scenario I described is as follows: 1. Initially, when I open Google Maps in a clean browser it defaults to my real location. 2. I repeatedly browse some other location. 3. When I open Google Maps in a clean browser, it defaults to that other location. The only reason for Google Maps to pick that other location is my map browsing.
But if you use those extensions, all your tooling breaks.
(Aside: I think the real bike-shedding would start when you want to add some syntax for raw string literals, e.g. heredocs; it's one of those features that feels redundant, until the day when you really need it and you can't bear the pain of repeatedly escaping and unescaping.)
https://github.com/toml-lang/toml/blob/main/toml.md#inline-t...
The Law of Large Numbers is about the average, so it's not relevant here (an average of +1 would mean you got heads every single time, which is extremely unlikely for large n).
If you are looking at the sum, then the value depends on whether the number of trials (n) is even or odd. If n is odd, you would indeed get two peaks at 1 and -1, and you would never get exactly 0. If n is even, you would get a peak at 0 and you would never get exactly 1 or -1.
The expected value (aka average) is a number, not a distribution. The expected value for the sum is 0 even when n is odd and you can't get exactly 0 -- that's just how the expected value works (in the same way that the "expected value" for the number of children in a family can be 2.5 even though a family can't have half a child). If you look at the probability density function for a single trial, then it does have two peaks at 1 and -1 (and is zero everywhere else).
The curve you refer to might be the normal approximation (https://en.wikipedia.org/wiki/Binomial_distribution#Normal_a...). It's true that the normal approximation for the distribution of the sum in your gambling game has a peak at 0 even when n is odd and the sum can't be exactly 0. That's because the normal approximation is a continuous approximation and it doesn't capture the discrete nature of the underlying distribution.
> Press I in a PR to hide comments.
Thank you! Comments can make it impossible to read the diff. And considering that by default anyone can post comments anywhere, this can be a serious issue. The other tips weren't that useful for me, but this one is a true gem (and is fairly well hidden -- no UI and hard to find in the docs; however when I pressed "?" it was listed in the keyboard shortcuts, which is actually how I discovered "?").
This trick (ping 3.3.3.3) is used to let a server behind NAT learn the IP address of a client that is also behind NAT, without requiring any non-NAT server (such as https://ifconfig.co).
The main action of this tool is to then create a UDP tunnel between the client and server.
But based on quick reading, the tool appears to assume that the NAT does not rewrite the UDP source port, so it won't work on all routers. STUN (which is used in e.g. WebRTC) implements more sophisticated techniques, and even then there are some cases where it cannot work and the only option is to use a relay (TURN).
I'm pretty sure that the same issue applies to the ping 3.3.3.3 trick -- if the NAT rewrites the ping identifier (as described in the article), the trick would break.
https://i.imgur.com/9cJ13ue.png (alternative link: https://imgur.com/a/uBG5KUD)
(The area of each circle is proportional to the count, clamped to a minimum value. Axes a are linear.)
Uses the data from https://viewports.fyi/data.csv.
Code:
import csv
from math import sqrt
import sys
csv_reader = csv.reader(sys.stdin)
headings = next(csv_reader)
data = [tuple(map(int, row[:3])) for row in csv_reader]
max_w = 7100 # max(row[0] for row in data) + fudge
max_h = 7100 # max(row[1] for row in data) + fudge
max_count = max(row[2] for row in data)
margin = 200
svg_width = max_w + 2*margin
svg_height = max_h + 2*margin
max_r = 90
min_r = 4
print('<?xml version="1.0"?>')
print(f'<svg xmlns="http://www.w3.org/2000/svg" width="{svg_width}" height="{svg_height}" viewBox="{-margin} {-margin} {svg_width} {svg_height}">')
print('<desc>Visualization of viewport sizes from https://viewports.fyi/</desc>')
print(f'<rect x="{-margin}" y="{-margin}" width="{svg_width}" height="{svg_height}" fill="white"/>')
print(f'<line x1="0" y1="0" x2="{max_w}" y2="0" stroke="black"/>')
print(f'<line x1="0" y1="0" x2="0" y2="{max_h}" stroke="black"/>')
for i in range(0, max_w, 200):
print(f'<text font-size="64" font-family="sans-serif" x="{i}" y="-30" text-anchor="middle">{i}</text>')
print(f'<line x1="{i}" y1="0" x2="{i}" y2="-20" stroke="black"/>')
for i in range(0, max_h, 200):
print(f'<text font-size="64" font-family="sans-serif" x="-30" y="{i + 20}" text-anchor="end">{i}</text>')
print(f'<line x1="0" y1="{i}" x2="-20" y2="{i}" stroke="black"/>')
print('<g fill="blue" stroke="darkblue">')
for w, h, count in data:
r = max(min_r, sqrt(count) / sqrt(max_count) * max_r)
print(f'<circle cx="{w}" cy="{h}" r="{r}"/>')
print('</g>')
print('</svg>')> The name of the project is inspired by the MPEG video standards group, together with "FF" for "fast forward"
Corresponding source (Fabrice Bellard himself): https://ffmpeg.org/pipermail/ffmpeg-devel/2006-February/0103...
> those two searches are exactly the same
Yes, that appears to be a recently-introduced typo -- the archived version from April does have a space: https://web.archive.org/web/20230412181331/https://support.g...
I submitted a feedback comment, hopefully they'll fix the typo.
(For future reference, here is a snapshot of the current version without a space: https://web.archive.org/web/20230722085337/https://support.g...)
bash -c 'exec 3<>/dev/tcp/$host/$port; cat >&3 | cat <&3'