As a studious GNU Units user, I have a small body of notes documenting various ways to perform calculations with unit conversions. Here are a few select ways that I found use of GNU units.

But first, a word about using GNU Units

GNU Units is a powerful, free calculator that performs unit conversions for you. Please check out the examples on GNU Units’ homepage to see what it is capable of.

I encourage users to read the GNU Units documentation (link to the HTML multi-page edition). Or read on the command line via info units or in Emacs via M-x info RET m units RET (or running emacs like emacs -Q --eval '(info "units")'). As a self test, you ought to know what ;, |, _, degC(), --verbose are for (hint, check the infopages index and this page!).

In order to understand its power, I recommend installing GNU Units on your phone (using something akin to Termux). Then use it whenever the need comes up to compute figures with unit conversions.

Calculate Aspartame intake via gum

Bought some especially hard gum to upkeep my jaw health called “Jawz Jaw Definining Gum Extra Tough Watermelon Gum”. Its ingredients are as follows:

sorbitol, gum base, xylitol, d-mannitol, moaltitol; less than 2% of: natural and artificial flavors, glycerin, citric acid, aspartame, acesulfame-k, bht to maintain freshness)

Each stick is 2.7g. Using GNU units, one can determine how much aspartame is contained in each stick:

units --quiet '2.7g 2%' mg

* 54
/ 0.018518519

From Wikipedia: According to EFSA acceptable daily intake (ADI) is 40mg/kg. FDA set ADI to 50mg/kg. Err on the side of caution. How many sticks a day can I consume before this intake approaches ADI?

units --quiet '161lb * 40mg/kg' 'mg'

* 2921.1349
/ 0.00034233271

Okay, that’s a lot of aspartame per day. Let’s calculate how many sticks:

units --quiet 'floor(161lb * 40mg/kg / 2.7g 2%)'

Definition: 54

So I can chew a ton of gum per day while maintaining ADI.

Determine grams per USD in protein powders

Comparing Dairy Free Vegan Protein Powder – Clean Simple Eats with Orgain Organic Vegan 21g Protein Powder - walmart.com

You have: (1.02 lb * (21g/46g)) / 19.59USD
You want: grams/USD
	(1.02 lb * (21g/46g)) / 19.59USD = 10.781841 grams/USD
	(1.02 lb * (21g/46g)) / 19.59USD = (1 / 0.092748535) grams/USD
You have: (990g * (18g/33g)) / 54.99USD
You want: grams/USD
	(990g * (18g/33g)) / 54.99USD = 9.8199673 grams/USD
	(990g * (18g/33g)) / 54.99USD = (1 / 0.10183333) grams/USD

Turns out Orgain is greater value but has peas so unsure about it.

Determine datarate for zfs send

1. check size in zfs list
2. run zfs send and check iostat -m output for MB/s written to storage

You have: (182 GB + 581 GB) / (33 MB/s)
You want: hours;minutes
        (182 GB + 581 GB) / (33 MB/s) = 6 hours + 25.353535 minutes

Currency exchange

winston@icarus ~ $ units
Currency exchange rates from exchangerate-api.com (USD base) on 2024-11-25
Consumer price index data from US BLS, 2024-11-24
7290 units, 125 prefixes, 169 nonlinear units

You have: 216.70 CZK
You want: USD
        * 8.9405605
        / 0.11184981
You have:

Shipping weight

Weigh myself on scale with then without the package:

You have: 182.7 lb - 172.0 lb
You want: lb;oz
	10 lb + 11.2 oz

That a wrap!

I have more examples tucked away in cobwebby folders stored on my less-used devices. And a lot more notes on unit conversions in general. Might be back with more unit nerd stuff…

In the meantime, check out some more examples in this Hacker News reply or this Reddit thread.

Python 3.14 was released today and I caught myself reading the Python 3.14 release notes so figured I’d type up what changes caught my eye.

Installing Python

There are probably better ways to do this. I opted to manually build and install Python 3.14:

./configure --prefix=$HOME/python3.14 && make -j && make install
export PATH="$HOME/python3.14/bin:$PATH"
which python3  # Should print out a path equivalent to $HOME/python3.14/bin/python3

python -m json

This is a nice way to pretty-print JSON (both indentation and color). Previously, one can use python -m json.tool. Now one can simply invoke python -m json. Personally, I missed the release of python -m json.tool, so this release note item helped introduce me to this built-in command line utility. Did you know about python -m json.tool?

Multiple performance improvements

The following areas saw significant performance improvements:

• uuid module
• garbage collection
• import time of a over 20 modules has been improved.
• asyncio subsystem performance improvements

compression.zstd

Python 3.14 now has ZSTD compression support built-in! ZSTD has pretty great characteristics for general use. One less pypi package to grab — hooray!

Attach pdb to a running Python process

Have a run away Python process? Attach pdb to it! In the screenshot, I’ve attached pdb to a toy roguelike that I created last year.

Simplified Exception specifications with PEP 758

Formerly you’d catch multiple exception types using a tuple except (ConnectionRefusedError, TimeoutError):. Now one can drop the parenthesis. It looks cleaner and less busy: except ConnectionRefusedError, TimeoutError:.

Color by default in more places!

Color now appears in argparse generated help messages. In the following picture, check out python -m http.server’s argparse message.

Oh, and python -m json prints in color by default now! (See the picture in the previous section for its colorfulness in action.)

Some other goodies

• pathlib’s Path objects gain copy() and move() methods to simplify file manipulation. Less reliance on shutil.copy and shutil.move.
• many more improvements - see the release notes!

What is your favorite recent Python addition?

I am curious regarding how many packages existed on my system. Then I got to wondering how many are Google projects? How many are Apache projects? Are all packages fully installed?

Get a list of packages into sqlite

First, one needs to create the sqlite3 file. The following bash script generates a .csv file with a header (that’s the echo command on the third line) and a dpkg-query incantation. Then the script prepares a sqlite file and imports the .csv as a SQLite table.

Yup, the .csv generation contains a minute hack. There are no restrictions on where commas may appear in most of these fields printed out using dpkg-query. However, by convention & in practice, I didn’t find any commas. But, you have been warned™.

tempfile=$(mktemp -t debianpackagecsv.XXXXXXXXXXXXX)
{
    echo 'Package,Version,Architecture,Homepage,Status'
    dpkg-query -W -f '"${Package}","${Version}","${Architecture}","${Homepage}","${Status}"\n'
} > "$tempfile"
sqlite3 packages.sqlite3 <<EOF
DROP TABLE IF EXISTS packages;
.mode csv
.import ${tempfile} packages
EOF
rm "$tempfile"
sqlite3 packages.sqlite3 'SELECT COUNT(*) FROM packages'

6143

As of my typing this text on my daily driver, this computer has 6182 packages installed. If the above number does not match 6182, it is probably due to installing more bloat, er, I mean, packages.

All fully installed packages (no config files)

Okay, now are all packages fully installed? This is Debian funny business.

sqlite3 packages.sqlite3 '
SELECT COUNT(*)
FROM packages
WHERE Status = "install ok installed"'

6034

Nope. The numbers don’t match. Something to look into, perhaps for another post.

If it ain’t broke, don’t fix it.

Or that’s what I like to remind myself when the personal computer tries to siphon off my time.

Google installed packages

Now let’s see how many packages are installed with Google in the Homepage?

sqlite3 packages.sqlite3 '
SELECT Package,Architecture,Homepage
FROM packages
WHERE Status = "install ok installed" AND Homepage LIKE "%google%";'

Whew! Thanks for scrolling. 69 packages. I didn’t know about zopfli. Apparently zopfli is a C library for compressing data using DEFLATE, gzip, and zlib compression formats. Moreover, zopfli is designed to generate the most compressed DEFLATE, gzip, zlib data. Meaning it’s slow to run but the storage sizes of the compressed data are less than other existing libraries.

Sidenote, apparently libarchive exists on a LOT of computers. Most infosec fans would agree that zlib is already a great supply chain attack vector if only for the sheer number of developers deploying zlib. Libarchive is getting up there! Libarchive ships on modern Windows and macOS. File interchange formats are hard to get right. Could libarchive be ripe for security research?

Apache packages

Similar invocation to the Google query. This time filter on Homepages with “Apache” in their text.

Yup 128 packages. Thanks for scrolling!

I hadn’t heard of ivy before. Upon a cursory flick through ivy’s homepage, it purportedly is the dependency resolver used in Apache Ant. Ant is a build tool not dissimilar to make in that it streamlines taking files and transforming the said files into derived data. One common example: a dependency manager can be employed to track dependencies when compiling a program from source code.

Something to try?

Something to try, for the curious: basic package stats — how many packages do you have installed? More pressingly, consider a stroll through the installed package list. Research a few unfamiliar packages. Do this a lot and you’ll understand virtually every individual software package on your computer.