.title {text-wrap:balance;} #content > p:first-child {text-wrap:balance;} If Git had a nemesis, it’d be large files. Large files bloat Git’s storage, slow down git clone, and wreak havoc on Git forges. In 2015, GitHub released Git LFS—a Git extension that hacked around problems with large files. But Git LFS added new complications and storage costs. Meanwhile, the Git project has been quietly working on large files. And while LFS ain’t dead yet, the latest Git release shows the path towards a future where LFS is, finally, obsolete. What you can do today: replace Git LFS with Git partial clone Git LFS works by storing large files outside your repo. When you clone a project via LFS, you get the repo’s history and small files, but skip large files. Instead, Git LFS downloads only the large files you need for your working copy. In 2017, the Git project introduced partial clones that provide the same benefits as Git LFS: Partial clone allows us to avoid downloading [large binary assets] in advance during clone and fetch operations and thereby reduce download times and disk usage. – Partial Clone Design Notes, git-scm.com Git’s partial clone and LFS both make for: Small checkouts – On clone, you get the latest copy of big files instead of every copy. Fast clones – Because you avoid downloading large files, each clone is fast. Quick setup – Unlike shallow clones, you get the entire history of the project—you can get to work right away. What is a partial clone? A Git partial clone is a clone with a --filter. For example, to avoid downloading files bigger than 100KB, you’d use: git clone --filter='blobs:size=100k' <repo> Later, Git will lazily download any files over 100KB you need for your checkout. By default, if I git clone a repo with many revisions of a noisome 25 MB PNG file, then cloning is slow and the checkout is obnoxiously large: $ time git clone https://github.com/thcipriani/noise-over-git Cloning into '/tmp/noise-over-git'... ... Receiving objects: 100% (153/153), 1.19 GiB real 3m49.052s Almost four minutes to check out a single 25MB file! $ du --max-depth=0 --human-readable noise-over-git/. 1.3G noise-over-git/. $ ^ 🤬 And 50 revisions of that single 25MB file eat 1.3GB of space. But a partial clone side-steps these problems: $ git config --global alias.pclone 'clone --filter=blob:limit=100k' $ time git pclone https://github.com/thcipriani/noise-over-git Cloning into '/tmp/noise-over-git'... ... Receiving objects: 100% (1/1), 24.03 MiB real 0m6.132s $ du --max-depth=0 --human-readable noise-over-git/. 49M noise-over-git/ $ ^ 😻 (the same size as a git lfs checkout) My filter made cloning 97% faster (3m 49s → 6s), and it reduced my checkout size by 96% (1.3GB → 49M)! But there are still some caveats here. If you run a command that needs data you filtered out, Git will need to make a trip to the server to get it. So, commands like git diff, git blame, and git checkout will require a trip to your Git host to run. But, for large files, this is the same behavior as Git LFS. Plus, I can’t remember the last time I ran git blame on a PNG 🙃. Why go to the trouble? What’s wrong with Git LFS? Git LFS foists Git’s problems with large files onto users. And the problems are significant: 🖕 High vendor lock-in – When GitHub wrote Git LFS, the other large file systems—Git Fat, Git Annex, and Git Media—were agnostic about the server-side. But GitHub locked users to their proprietary server implementation and charged folks to use it.1 💸 Costly – GitHub won because it let users host repositories for free. But Git LFS started as a paid product. Nowadays, there’s a free tier, but you’re dependent on the whims of GitHub to set pricing. Today, a 50GB repo on GitHub will cost $40/year for storage. In contrast, storing 50GB on Amazon’s S3 standard storage is $13/year. 😰 Hard to undo – Once you’ve moved to Git LFS, it’s impossible to undo the move without rewriting history. 🌀 Ongoing set-up costs – All your collaborators need to install Git LFS. Without Git LFS installed, your collaborators will get confusing, metadata-filled text files instead of the large files they expect. The future: Git large object promisors Large files create problems for Git forges, too. GitHub and GitLab put limits on file size2 because big files cost more money to host. Git LFS keeps server-side costs low by offloading large files to CDNs. But the Git project has a new solution. Earlier this year, Git merged a new feature: large object promisers. Large object promisors aim to provide the same server-side benefits as LFS, minus the hassle to users. This effort aims to especially improve things on the server side, and especially for large blobs that are already compressed in a binary format. This effort aims to provide an alternative to Git LFS – Large Object Promisors, git-scm.com What is a large object promisor? Large object promisors are special Git remotes that only house large files. In the bright, shiny future, large object promisors will work like this: You push a large file to your Git host. In the background, your Git host offloads that large file to a large object promisor. When you clone, the Git host tells your Git client about the promisor. Your client will clone from the Git host, and automagically nab large files from the promisor remote. But we’re still a ways off from that bright, shiny future. Git large object promisors are still a work in progress. Pieces of large object promisors merged to Git in March of 2025. But there’s more to do and open questions yet to answer. And so, for today, you’re stuck with Git LFS for giant files. But once large object promisors see broad adoption, maybe GitHub will let you push files bigger than 100MB. The future of large files in Git is Git. The Git project is thinking hard about large files, so you don’t have to. Today, we’re stuck with Git LFS. But soon, the only obstacle for large files in Git will be your half-remembered, ominous hunch that it’s a bad idea to stow your MP3 library in Git. Edited by Refactoring English Later, other Git forges made their own LFS servers. Today, you can push to multiple Git forges or use an LFS transfer agent, but all this makes set up harder for contributors. You’re pretty much locked-in unless you put in extra effort to get unlocked.↩︎ File size limits: 100MB for GitHub, 100MB for GitLab.com↩︎

Any code of your own that you haven’t looked at for six or more months might as well have been written by someone else. – Eagleson’s Law After scouring git history, I found the correct config file, but someone removed it. Their full commit message read: Remove config. Don't bring it back. Very. helpful. But I get it; it’s hard to care about commit messages when you’re making a quick change. Git commit templates can help. Commit templates provide a scaffold for your commit messages, reminding you to answer questions like: What problem are you solving? Why is this the solution? What alternatives did you consider? Where can I read more? What is a git commit template? When you type git commit, git pops open your text editor1. Git can pre-fill your editor with a commit template—a form that reminds you of everything it’s easy to forget when writing a commit. Creating a commit template is simple. Create a plaintext file – mine lives at ~/.config/git/message.txt Tell git to use it: git config --global \ commit.template '~/.config/git/message.txt' My template packs everything I know about writing a commit. Project-specific templates Large projects, such as Linux kernel, git, and MediaWiki, have their own commit guidelines. Git templates can remind you about these per-project requirements if you add a commit template to a project’s .git/config file. Another way to do this is git’s includeIf configuration setting. includeIf lets you override git config settings when you’re working under directories you define. For example, all my Wikimedia work lives in ~/Projects/Wikimedia and at the bottom of my ~/.config/git/config I have: [includeIf "gitdir:~/Projects/Wikimedia/**"] path = ~/.config/git/config.wikimedia In config.wikimedia, I point to my Wikimedia-specific commit template (along with other necessary git settings: my user.email, core.hooksPath, and a pushInsteadOf url to push to ssh even when I clone via https). Forge-specific templates Personal git commit templates lead to better commits, which make for a better history. The forge-specific pull-request templates are a band-aid, the cheap kind that falls off in the shower. There’s no incentive for GitHub to make git history better: the worse your commit history, the more you rely on GitHub. Still, all the major pull-request-style forges let you foist a pull-request template on your contributors. As a contributor, I dislike filling those out—they add unnecessary friction. Commit message contents Your commit template allows you do the hard thinking upfront. Then, when you make a commit, you simply follow the template. My template asks questions I answer with my commit message: 72ch. wide -------------------------------------------------------- BODY # | # - Why should this change be made? | # - What problem are you solving? | # - Why this solution? | # - What's wrong with the current code? | # - Are there other ways to do it? | # - How can the reviewer confirm it works? | # | # ---------------------------------------------------------------- /BODY But other clever folks cooked up conventions you could incorporate: Conventional commits – how do your commits relate to semantic versioning? This makes it easier for SRE and downstream users. Problem/Solution format – first pioneered by ZeroMQ2, this format anticipates the questions of future developers and reviewers. Gitmoji – developed for the GitHub crowd, this format defines an emoji shorthand that makes it easy to spot changes of a particular type. Commit message formatting How you format text affects how people read it. My template also deals with text formatting rules3: Subject – 50 characters or less, capitalized, no end punctuation. Body – Wrap at 72 characters with a blank line separating it from the subject. Trailers – Standard formats with a blank line separating them from the body. People will read your commit in different contexts: git log, git shortlog, and git rebase. But git’s pager has no line wrapping by default. I hard wrap at 72 characters because that makes text easier to read in wide terminals.4 Finally, my template addresses trailers, reminding me about standard trailers supported in the projects I’m working on. Git can interpret trailers, which can be useful later. For example, if I wanted a tab-separated list of commits and their related tasks I could find that with git log: $ TAB=%x09 $ BUG_TRAILER='%(trailers:key=Bug,valueonly=true,separator=%x2C )' $ SHORT_HASH=%h $ SUBJ=%s $ FORMAT="${SHORT_HASH}${TAB}${BUG_TRAILER}${TAB}${GIT_SUBJ}" $ git log --topo-order --no-merges \ --format="$FORMAT" d2b09deb12f T359762 Rewrite Kurdish (ku) Latin to Arabic converter 28123a6a262 T332865 tests: Remove non-static fallback in HookRunnerTestBase 4e919a307a4 T328919 tests: Remove unused argument from data provider in PageUpdaterTest bedd0f685f9 objectcache: Improve `RESTBagOStuff::handleError()` 2182a0c4490 T393219 tests: Remove two data provider in RestStructureTest Git commit templates free your brain from remembering what you should write, allowing you to focus on the story you should tell. Your future self will thank you for the effort. Starting with core.editor in your git config, $VISUAL or $EDITOR in your shell, finally falling back to vi.↩︎ I think…↩︎ All cribbed from Tim Pope↩︎ Another story I’ve heard: a standard terminal allows 80 characters per line. git log indents commit messages with 4 spaces. A 72-character-per-line commit centers text on an 80-character-per-line terminal. To me, readability in modern terminals is a better reason to wrap than kowtowing to antiquated terminals.↩︎

[The] Linux kernel uses GPLv2, and if you distribute GPLv2 code, you have to provide a copy of the source (and modifications) once someone asks for it. And now I’m asking nicely for you to do so 🙂 – Joga, bbs.onyx-international.com Boox in split screen, typewriter mode In January, I bought a Boox Go 10.3—a 10.3-inch, 300-ppi, e-ink Android tablet. After two months, I use the Boox daily—it’s replaced my planner, notebook, countless PDF print-offs, and the good parts of my phone. But Boox’s parent company, Onyx, is sketchy. I’m conflicted. The Boox Go is a beautiful, capable tablet that I use every day, but I recommend avoiding as long as Onyx continues to disregard the rights of its users. How I’m using my Boox My e-ink floor desk Each morning, I plop down in front of my MagicHold laptop stand and journal on my Boox with Obsidian. I use Syncthing to back up my planner and sync my Zotero library between my Boox and laptop. In the evening, I review my PDF planner and plot for tomorrow. I use these apps: Obsidian – a markdown editor that syncs between all my devices with no fuss for $8/mo. Syncthing – I love Syncthing—it’s an encrypted, continuous file sync-er without a centralized server. Meditation apps1 – Guided meditation away from the blue light glow of my phone or computer is better. Before buying the Boox, I considered a reMarkable. The reMarkable Paper Pro has a beautiful color screen with a frontlight, a nice pen, and a “type folio,” plus it’s certified by the Calm Tech Institute. But the reMarkable is a distraction-free e-ink tablet. Meanwhile, I need distraction-lite. What I like Calm(ish) technology – The Boox is an intentional device. Browsing the internet, reading emails, and watching videos is hard, but that’s good. Apps – Google Play works out of the box. I can install F-Droid and change my launcher without difficulty. Split screen – The built-in launcher has a split screen feature. I use it to open a PDF side-by-side with a notes doc. Reading – The screen is a 300ppi Carta 1200, making text crisp and clear. What I dislike I filmed myself typing at 240fps, each frame is 4.17ms. Boox’s typing latency is between 150ms and 275ms at the fastest refresh rate inside Obsidian. Typing – Typing latency is noticeable. At Boox’s highest refresh rate, after hitting a key, text takes between 150ms to 275ms to appear. I can still type, though it’s distracting at times. The horror of the default pen Accessories Pen – The default pen looks like a child’s whiteboard marker and feels cheap. I replaced it with the Kindle Scribe Premium pen, and the writing experience is vastly improved. Cover – It’s impossible to find a nice cover. I’m using a $15 cover that I’m encasing in stickers. Tool switching – Swapping between apps is slow and clunky. I blame Android and the current limitations of e-ink more than Boox. No frontlight – The Boox’s lack of frontlight prevents me from reading more with it. I knew this when I bought my Boox, but devices with frontlights seem to make other compromises. Onyx The Chinese company behind Boox, Onyx International, Inc., runs the servers where Boox shuttles tracking information. I block this traffic with Pi-Hole2. pihole-ing whatever telemetry Boox collects I inspected this traffic via Mitm proxy—most traffic was benign, though I never opted into sending any telemetry (nor am I logged in to a Boox account). But it’s also an Android device, so it’s feeding telemetry into Google’s gaping maw, too. Worse, Onyx is flouting the terms of the GNU Public License, declining to release Linux kernel modifications to users. This is anathema to me—GPL violations are tantamount to theft. Onyx’s disregard for user rights makes me regret buying the Boox. Verdict I’ll continue to use the Boox and feel bad about it. I hope my digging in this post will help the next person. Unfortunately, the e-ink tablet market is too niche to support the kind of solarpunk future I’d always imagined. But there’s an opportunity for an open, Linux-based tablet to dominate e-ink. Linux is playing catch-up on phones with PostmarketOS. Meanwhile, the best e-ink tablets have to offer are old, unupdateable versions of Android, like the OS on the Boox. In the future, I’d love to pay a license- and privacy-respecting company for beautiful, calm technology and recommend their product to everyone. But today is not the future. I go back and forth between “Waking Up” and “Calm”↩︎ Using github.com/JordanEJ/Onyx-Boox-Blocklist↩︎

.title { text-wrap: balance } Spending for October, generated by piping hledger → R Over the past six months, I’ve tracked my money with hledger—a plain text double-entry accounting system written in Haskell. It’s been surprisingly painless. My previous attempts to pick up real accounting tools floundered. Hosted tools are privacy nightmares, and my stint with GnuCash didn’t last. But after stumbling on Dmitry Astapov’s “Full-fledged hledger” wiki1, it clicked—eventually consistent accounting. Instead of modeling your money all at once, take it one hacking session at a time. It should be easy to work towards eventual consistency. […] I should be able to [add financial records] bit by little bit, leaving things half-done, and picking them up later with little (mental) effort. – Dmitry Astapov, Full-Fledged Hledger Principles of my system I’ve cobbled together a system based on these principles: Avoid manual entry – Avoid typing in each transaction. Instead, rely on CSVs from the bank. CSVs as truth – CSVs are the only things that matter. Everything else can be blown away and rebuilt anytime. Embrace version control – Keep everything under version control in Git for easy comparison and safe experimentation. Learn hledger in five minutes hledger concepts are heady, but its use is simple. I divide the core concepts into two categories: Stuff hledger cares about: Transactions – how hledger moves money between accounts. Journal files – files full of transactions Stuff I care about: Rules files – how I set up accounts, import CSVs, and move money between accounts. Reports – help me see where my money is going and if I messed up my rules. Transactions move money between accounts: 2024-01-01 Payday income:work $-100.00 assets:checking $100.00 This transaction shows that on Jan 1, 2024, money moved from income:work into assets:checking—Payday. The sum of each transaction should be $0. Money comes from somewhere, and the same amount goes somewhere else—double-entry accounting. This is powerful technology—it makes mistakes impossible to ignore. Journal files are text files containing one or more transactions: 2024-01-01 Payday income:work $-100.00 assets:checking $100.00 2024-01-02 QUANSHENG UVK5 assets:checking $-29.34 expenses:fun:radio $29.34 Rules files transform CSVs into journal files via regex matching. Here’s a CSV from my bank: Transaction Date,Description,Category,Type,Amount,Memo 09/01/2024,DEPOSIT Paycheck,Payment,Payment,1000.00, 09/04/2024,PizzaPals Pizza,Food & Drink,Sale,-42.31, 09/03/2024,Amazon.com*XXXXXXXXY,Shopping,Sale,-35.56, 09/03/2024,OBSIDIAN.MD,Shopping,Sale,-10.00, 09/02/2024,Amazon web services,Personal,Sale,-17.89, And here’s a checking.rules to transform that CSV into a journal file so I can use it with hledger: # checking.rules # -------------- # Map CSV fields → hledger fields[0] fields date,description,category,type,amount,memo,_ # `account1`: the account for the whole CSV.[1] account1 assets:checking account2 expenses:unknown skip 1 date-format %m/%d/%Y currency $ if %type Payment account2 income:unknown if %category Food & Drink account2 expenses:food:dining # [0]: <https://hledger.org/hledger.html#field-names> # [1]: <https://hledger.org/hledger.html#account-field> With these two files (checking.rules and 2024-09_checking.csv), I can make the CSV into a journal: $ > 2024-09_checking.journal \ hledger print \ --rules-file checking.rules \ -f 2024-09_checking.csv $ head 2024-09_checking.journal 2024-09-01 DEPOSIT Paycheck assets:checking $1000.00 income:unknown $-1000.00 2024-09-02 Amazon web services assets:checking $-17.89 expenses:unknown $17.89 Reports are interesting ways to view transactions between accounts. There are registers, balance sheets, and income statements: $ hledger incomestatement \ --depth=2 \ --file=2024-09_bank.journal Revenues: $1000.00 income:unknown ----------------------- $1000.00 Expenses: $42.31 expenses:food $63.45 expenses:unknown ----------------------- $105.76 ----------------------- Net: $894.24 At the beginning of September, I spent $105.76 and made $1000, leaving me with $894.24. But a good chunk is going to the default expense account, expenses:unknown. I can use the hleger aregister to see what those transactions are: $ hledger areg expenses:unknown \ --file=2024-09_checking.journal \ -O csv | \ csvcut -c description,change | \ csvlook | description | change | | ------------------------ | ------ | | OBSIDIAN.MD | 10.00 | | Amazon web services | 17.89 | | Amazon.com*XXXXXXXXY | 35.56 | l Then, I can add some more rules to my checking.rules: if OBSIDIAN.MD account2 expenses:personal:subscriptions if Amazon web services account2 expenses:personal:web:hosting if Amazon.com account2 expenses:personal:shopping:amazon Now, I can reprocess my data to get a better picture of my spending: $ > 2024-09_bank.journal \ hledger print \ --rules-file bank.rules \ -f 2024-09_bank.csv $ hledger bal expenses \ --depth=3 \ --percent \ -f 2024-09_checking2.journal 30.0 % expenses:food:dining 33.6 % expenses:personal:shopping 9.5 % expenses:personal:subscriptions 16.9 % expenses:personal:web -------------------- 100.0 % For the Amazon.com purchase, I lumped it into the expenses:personal:shopping account. But I could dig deeper—download my order history from Amazon and categorize that spending. This is the power of working bit-by-bit—the data guides you to the next, deeper rabbit hole. Goals and non-goals Why am I doing this? For years, I maintained a monthly spreadsheet of account balances. I had a balance sheet. But I still had questions. Spending over six months, generated by piping hledger → gnuplot Before diving into accounting software, these were my goals: Granular understanding of my spending – The big one. This is where my monthly spreadsheet fell short. I knew I had money in the bank—I kept my monthly balance sheet. I budgeted up-front the % of my income I was saving. But I had no idea where my other money was going. Data privacy – I’m unwilling to hand the keys to my accounts to YNAB or Mint. Increased value over time – The more time I put in, the more value I want to get out—this is what you get from professional tools built for nerds. While I wished for low-effort setup, I wanted the tool to be able to grow to more uses over time. Non-goals—these are the parts I never cared about: Investment tracking – For now, I left this out of scope. Between monthly balances in my spreadsheet and online investing tools’ ability to drill down, I was fine.2 Taxes – Folks smarter than me help me understand my yearly taxes.3 Shared system – I may want to share reports from this system, but no one will have to work in it except me. Cash – Cash transactions are unimportant to me. I withdraw money from the ATM sometimes. It evaporates. hledger can track all these things. My setup is flexible enough to support them someday. But that’s unimportant to me right now. Monthly maintenance I spend about an hour a month checking in on my money Which frees me to spend time making fancy charts—an activity I perversely enjoy. Income vs. Expense, generated by piping hledger → gnuplot Here’s my setup: $ tree ~/Documents/ledger . ├── export │   ├── 2024-balance-sheet.txt │   └── 2024-income-statement.txt ├── import │   ├── in │   │   ├── amazon │   │   │   └── order-history.csv │   │   ├── credit │   │   │   ├── 2024-01-01_2024-02-01.csv │   │   │   ├── ... │   │   │   └── 2024-10-01_2024-11-01.csv │   │   └── debit │   │   ├── 2024-01-01_2024-02-01.csv │   │   ├── ... │   │   └── 2024-10-01_2024-11-01.csv │   └── journal │   ├── amazon │   │   └── order-history.journal │   ├── credit │   │   ├── 2024-01-01_2024-02-01.journal │   │   ├── ... │   │   └── 2024-10-01_2024-11-01.journal │   └── debit │   ├── 2024-01-01_2024-02-01.journal │   ├── ... │   └── 2024-10-01_2024-11-01.journal ├── rules │   ├── amazon │   │   └── journal.rules │   ├── credit │   │   └── journal.rules │   ├── debit │   │   └── journal.rules │   └── common.rules ├── 2024.journal ├── Makefile └── README Process: Import – download a CSV for the month from each account and plop it into import/in/<account>/<dates>.csv Make – run make Squint – Look at git diff; if it looks good, git add . && git commit -m "💸" otherwise review hledger areg to see details. The Makefile generates everything under import/journal: journal files from my CSVs using their corresponding rules. reports in the export folder I include all the journal files in the 2024.journal with the line: include ./import/journal/*/*.journal Here’s the Makefile: SHELL := /bin/bash RAW_CSV = $(wildcard import/in/**/*.csv) JOURNALS = $(foreach file,$(RAW_CSV),$(subst /in/,/journal/,$(patsubst %.csv,%.journal,$(file)))) .PHONY: all all: $(JOURNALS) hledger is -f 2024.journal > export/2024-income-statement.txt hledger bs -f 2024.journal > export/2024-balance-sheet.txt .PHONY clean clean: rm -rf import/journal/**/*.journal import/journal/%.journal: import/in/%.csv @echo "Processing csv $< to $@" @echo "---" @mkdir -p $(shell dirname $@) @hledger print --rules-file rules/$(shell basename $$(dirname $<))/journal.rules -f "$<" > "$@" If I find anything amiss (e.g., if my balances are different than what the bank tells me), I look at hleger areg. I may tweak my rules or my CSVs and then I run make clean && make and try again. Simple, plain text accounting made simple. And if I ever want to dig deeper, hledger’s docs have more to teach. But for now, the balance of effort vs. reward is perfect. while reading a blog post from Jonathan Dowland↩︎ Note, this is covered by full-fledged hledger – Investements↩︎ Also covered in full-fledged hledger – Tax returns↩︎

Luckily, I speak Leet. – Amita Ramanujan, Numb3rs, CBS’s IRC Drama There’s an episode of the CBS prime-time drama Numb3rs that plumbs the depths of Dr. Joel Fleischman’s1 knowledge of IRC. In one scene, Fleischman wonders, “What’s ‘leet’”? “Leet” is writing that replaces letters with numbers, e.g., “Numb3rs,” where 3 stands in for e. In short, leet is like the heavy-metal “S” you drew in middle school: Sweeeeet. / \ / | \ | | | \ \ | | | \ | / \ / ASCII art version of your misspent youth. Following years of keen observation, I’ve noticed Git commit hashes are also letters and numbers. Git commit hashes are, as Fleischman might say, prime targets for l33tification. What can I spell with a git commit? DenITDao via orlybooks) With hexidecimal we can spell any word containing the set of letters {A, B, C, D, E, F}—DEADBEEF (a classic) or ABBABABE (for Mama Mia aficionados). This is because hexidecimal is a base-16 numbering system—a single “digit” represents 16 numbers: Base-10: 0 1 2 3 4 5 6 7 8 9 10 11 12 13 16 15 Base-16: 0 1 2 3 4 5 6 7 8 9 A B C D E F Leet expands our palette of words—using 0, 1, and 5 to represent O, I, and S, respectively. I created a script that scours a few word lists for valid words and phrases. With it, I found masterpieces like DADB0D (dad bod), BADA55 (bad ass), and 5ADBAB1E5 (sad babies). Manipulating commit hashes for fun and no profit Git commit hashes are no mystery. A commit hash is the SHA-1 of a commit object. And a commit object is the commit message with some metadata. $ mkdir /tmp/BADA55-git && cd /tmp/BAD55-git $ git init Initialized empty Git repository in /tmp/BADA55-git/.git/ $ echo '# BADA55 git repo' > README.md && git add README.md && git commit -m 'Initial commit' [main (root-commit) 68ec0dd] Initial commit 1 file changed, 1 insertion(+) create mode 100644 README.md $ git log --oneline 68ec0dd (HEAD -> main) Initial commit Let’s confirm we can recreate the commit hash: $ git cat-file -p 68ec0dd > commit-msg $ sha1sum <(cat \ <(printf "commit ") \ <(wc -c < commit-msg | tr -d '\n') \ <(printf '%b' '\0') commit-msg) 68ec0dd6dead532f18082b72beeb73bd828ee8fc /dev/fd/63 Our repo’s first commit has the hash 68ec0dd. My goal is: Make 68ec0dd be BADA55. Keep the commit message the same, visibly at least. But I’ll need to change the commit to change the hash. To keep those changes invisible in the output of git log, I’ll add a \t and see what happens to the hash. $ truncate -s -1 commit-msg # remove final newline $ printf '\t\n' >> commit-msg # Add a tab $ # Check the new SHA to see if it's BADA55 $ sha1sum <(cat \ <(printf "commit ") \ <(wc -c < commit-msg | tr -d '\n') \ <(printf '%b' '\0') commit-msg) 27b22ba5e1c837a34329891c15408208a944aa24 /dev/fd/63 Success! I changed the SHA-1. Now to do this until we get to BADA55. Fortunately, user not-an-aardvark created a tool for that—lucky-commit that manipulates a commit message, adding a combination of \t and [:space:] characters until you hit a desired SHA-1. Written in rust, lucky-commit computes all 256 unique 8-bit strings composed of only tabs and spaces. And then pads out commits up to 48-bits with those strings, using worker threads to quickly compute the SHA-12 of each commit. It’s pretty fast: $ time lucky_commit BADA555 real 0m0.091s user 0m0.653s sys 0m0.007s $ git log --oneline bada555 (HEAD -> main) Initial commit $ xxd -c1 <(git cat-file -p 68ec0dd) | grep -cPo ': (20|09)' 12 $ xxd -c1 <(git cat-file -p HEAD) | grep -cPo ': (20|09)' 111 Now we have an more than an initial commit. We have a BADA555 initial commit. All that’s left to do is to make ALL our commits BADA55 by abusing git hooks. $ cat > .git/hooks/post-commit && chmod +x .git/hooks/post-commit #!/usr/bin/env bash echo 'L337-ifying!' lucky_commit BADA55 $ echo 'A repo that is very l33t.' >> README.md && git commit -a -m 'l33t' L337-ifying! [main 0e00cb2] l33t 1 file changed, 1 insertion(+) $ git log --oneline bada552 (HEAD -> main) l33t bada555 Initial commit And now I have a git repo almost as cool as the sweet “S” I drew in middle school. This is a Northern Exposure spin off, right? I’ve only seen 1:48 of the show…↩︎ or SHA-256 for repos that have made the jump to a more secure hash function↩︎