Merge bc767a0ad3 into b329d36888

README.md

@@ -10,7 +10,7 @@ pairing with smart people at Hashrocket.
 
 For a steady stream of TILs, [sign up for my newsletter](https://crafty-builder-6996.ck.page/e169c61186).
 
-_1514 TILs and counting..._
+_1520 TILs and counting..._
 
 ---
 
@@ -41,6 +41,7 @@ _1514 TILs and counting..._
 * [Internet](#internet)
 * [Java](#java)
 * [JavaScript](#javascript)
+* [jj](#jj)
 * [jq](#jq)
 * [Kitty](#kitty)
 * [Linux](#linux)
@@ -310,6 +311,7 @@ _1514 TILs and counting..._
 - [Find And Remove Files That Match A Name](git/find-and-remove-files-that-match-a-name.md)
 - [Find The Date That A File Was Added To The Repo](git/find-the-date-that-a-file-was-added-to-the-repo.md)
 - [Find The Initial Commit](git/find-the-initial-commit.md)
+- [Get Latest Commit Timestamp For A File](git/get-latest-commit-timestamp-for-a-file.md)
 - [Get The Name Of The Current Branch](git/get-the-name-of-the-current-branch.md)
 - [Get The Short Version Of The Latest Commit](git/get-the-short-version-of-the-latest-commit.md)
 - [Grab A Single File From A Stash](git/grab-a-single-file-from-a-stash.md)
@@ -568,6 +570,10 @@ _1514 TILs and counting..._
 - [Yarn Commands Without The Emojis](javascript/yarn-commands-without-the-emojis.md)
 - [Yup Schemas Are Validated Asynchronously](javascript/yup-schemas-are-validated-asynchronously.md)
 
+### jj
+
+- [Colocate jj And git Directories For Project](jj/colocate-jj-and-git-directories-for-project.md)
+
 ### jq
 
 - [Combine An Array Of Objects Into A Single Object](jq/combine-an-array-of-objects-into-a-single-object.md)
@@ -1182,6 +1188,7 @@ _1514 TILs and counting..._
 - [Audit Your Ruby Project For Any CVEs](ruby/audit-your-ruby-project-for-any-cves.md)
 - [Assoc For Hashes](ruby/assoc-for-hashes.md)
 - [Block Comments](ruby/block-comments.md)
+- [Block Syntaxes Have Different Precedence](ruby/block-syntaxes-have-different-precedence.md)
 - [Build HTTP And HTTPS URLs](ruby/build-http-and-https-urls.md)
 - [Chaining Multiple RSpec Change Matchers](ruby/chaining-multiple-rspec-change-matchers.md)
 - [Check For Any Overlaps In List Of Ranges](ruby/check-for-any-overlaps-in-list-of-ranges.md)
@@ -1225,6 +1232,7 @@ _1514 TILs and counting..._
 - [Finding The Source of Ruby Methods](ruby/finding-the-source-of-ruby-methods.md)
 - [Format A Hash Into A String Template](ruby/format-a-hash-into-a-string-template.md)
 - [Forward All Arguments To Another Method](ruby/forward-all-arguments-to-another-method.md)
+- [Gather Positional Arguments In Method Definition](ruby/gather-positional-arguments-in-method-definition.md)
 - [Generate A Signed JWT Token](ruby/generate-a-signed-jwt-token.md)
 - [Generate Ruby Version And Gemset Files With RVM](ruby/generate-ruby-version-and-gemset-files-with-rvm.md)
 - [Get Info About Your RubyGems Environment](ruby/get-info-about-your-ruby-gems-environment.md)
@@ -1292,6 +1300,7 @@ _1514 TILs and counting..._
 - [Specify How Random Array#sample Is](ruby/specify-how-random-array-sample-is.md)
 - [Split A Float Into Its Integer And Decimal](ruby/split-a-float-into-its-integer-and-decimal.md)
 - [Squeeze Out The Extra Space](ruby/squeeze-out-the-extra-space.md)
+- [Stack Heredocs In A Method Call](ruby/stack-heredocs-in-a-method-call.md)
 - [String Interpolation With Instance Variables](ruby/string-interpolation-with-instance-variables.md)
 - [Summing Collections](ruby/summing-collections.md)
 - [Triple Equals: The Case Equality Operator](ruby/triple-equals-the-case-equality-operator.md)
@@ -1537,6 +1546,7 @@ _1514 TILs and counting..._
 - [Switch Versions of a Brew Formula](unix/switch-versions-of-a-brew-formula.md)
 - [Tell direnv To Load The Env File](unix/tell-direnv-to-load-the-env-file.md)
 - [Touch Access And Modify Times Individually](unix/touch-access-and-modify-times-individually.md)
+- [Type Fewer Paths With Brace Expansion](unix/type-fewer-paths-with-brace-expansion.md)
 - [Undo Changes Made To Current Terminal Prompt](unix/undo-changes-made-to-current-terminal-prompt.md)
 - [Undo Some Command Line Editing](unix/undo-some-command-line-editing.md)
 - [Unrestrict Where ripgrep Searches](unix/unrestrict-where-ripgrep-searches.md)

git/get-latest-commit-timestamp-for-a-file.md

@@ -0,0 +1,25 @@
+# Get Latest Commit Timestamp For A File
+
+The `git log` command can tell you all the commits that touched a file. That
+can be narrowed down to the latest commit for that file with the `-1` flag. The
+commit that it reports can then be further formatted to with the `--format`
+flag.
+
+The `%ai` format pattern gives the date the commit was authored in an ISO
+8601-like format. The `%aI` (capital `I`) gives the date the commit was
+authored strictly in the ISO 8601 format.
+
+Here are examples of both side by side:
+
+```bash
+❯ git log -1 --format=%ai -- README.md
+2024-10-15 13:59:09 -0500
+
+❯ git log -1 --format=%aI -- README.md
+2024-10-15T13:59:09-05:00
+```
+
+I made use of this in a script where I needed to get an idea of when various
+files were most recently modified.
+
+See `man git-log` and the `PRETTY FORMATS` section for more details.

jj/colocate-jj-and-git-directories-for-project.md

@@ -0,0 +1,59 @@
+# Colocate jj And git Directories For Project
+
+When doing a standard clone of a git repository with `jj`, you'll get a copy of
+the project with a `.jj` directory containing the version control information.
+
+```bash
+$ jj git clone git@github.com:jbranchaud/my-repo
+Fetching into new repo in "/path/of/local/repo"
+...
+
+$ exa --tree --all -L 1
+.
+├── .gitignore
+├── .jj
+├── Cargo.lock
+├── Cargo.toml
+└── src
+```
+
+This is fine if I'm completely familiar with using
+[jujutsu](https://martinvonz.github.io/jj/latest/). However, if I'm coming from
+`git` and still learning, then it would be nice to be able to fallback to
+familiar `git` commands when needed.
+
+But without a `.git` directory, I get this:
+
+```bash
+$ git log
+fatal: not a git repository (or any of the parent directories): .git
+```
+
+When cloning a git repo with `jj`, I can instruct it to _colocate_ which means
+that it will create both the `.jj` and the `.git` data directories in the
+project.
+
+```bash
+$ jj git clone --colocate git@github.com:jbranchaud/my-repo
+Fetching into new repo in "/path/of/local/repo"
+...
+
+$ exa --tree --all -L 1
+.
+├── .git
+├── .gitignore
+├── .jj
+├── Cargo.lock
+├── Cargo.toml
+└── src
+```
+
+Now I can run `jj` commands or `git` commands:
+
+```bash
+$ git log
+commit 0c72abbb83657096677f9a3d5ddc7bce20839165 (HEAD, origin/trunk, trunk)
+...
+```
+
+[source](https://martinvonz.github.io/jj/latest/git-compatibility/#co-located-jujutsugit-repos)

ruby/block-syntaxes-have-different-precedence.md

@@ -0,0 +1,29 @@
+# Block Syntaxes Have Different Precedence
+
+There are two syntaxes for defining a block in Ruby. The semantically shorthand
+syntax uses the curly braces (`{}`). The semantically multi-line syntax uses
+`do` and `end`. For nearly all intents and purposes they are interchangable.
+
+It is, however, worth noting that the `do`/`end` version has a lower precedence
+than the already low precedence of `{}`. That said, you have to write some
+weird code for this to become an issue.
+
+Let's say we have two methods, `method_one` and `method_two`. They are both
+called on the same line like below and then followed by a block argument. Which
+method receives the block argument?
+
+```ruby
+method_one method_two { |n|
+  puts "Executing a block: #{n}"
+}
+
+method_one method_two do |n|
+  puts "Executing a block: #{n}"
+end
+```
+
+In the first case, with the curly braces, `method_two` receives the block as an
+argument. In the second case, with the `do`/`end`, `method_one` receives the
+block as an argument.
+
+[source](http://localhost:3131/ruby-operators/curly-braces#block-shorthand)

ruby/gather-positional-arguments-in-method-definition.md

@@ -0,0 +1,55 @@
+# Gather Positional Arguments In Method Definition
+
+The `*` symbol can be used in Ruby in a method definition to gather up an
+arbitrary number of positional arguments.
+
+For instance, we can gather all positional arguments with this method
+definition:
+
+```ruby
+def gather_all(*args)
+  puts args
+end
+```
+
+Or we can isolate the first positional arg and then gather the rest:
+
+```ruby
+def first_and_rest(first, *rest)
+  puts "First: #{first}, Rest: #{rest}"
+end
+```
+
+We can even do something a bit more interesting like isolating the first and
+last arguments while gathering up everything else in the middle:
+
+```ruby
+def pop_parens(left, *middle, right)
+  if left != '(' || right != ')'
+    raise "Uh oh!"
+  else
+    if middle.size == 1
+      puts "Found: #{middle.first}"
+    else
+      pop_parens(*middle)
+    end
+  end
+end
+```
+
+Here is what it looks like if we splat some different sets of arguments into
+that method call:
+
+```ruby
+> tokens1 = "((((4))))".split('')
+=> ["(", "(", "(", "(", "4", ")", ")", ")", ")"]
+> tokens2 = "((4))))".split('')
+=> ["(", "(", "4", ")", ")", ")", ")"]
+> pop_parens(*tokens1)
+Found: 4
+=> nil
+> pop_parens(*tokens2)
+(irb):87:in `pop_parens': Uh oh! (RuntimeError)
+```
+
+[source](https://ruby-doc.org/3.3.6/syntax/methods_rdoc.html#label-Array-2FHash+Argument)

ruby/stack-heredocs-in-a-method-call.md

@@ -0,0 +1,37 @@
+# Stack Heredocs In A Method Call
+
+When you put a heredoc directly in a method call as an argument, it is only the
+opening identifier that goes in the argument list.
+
+That looks like this:
+
+```ruby
+execute_in_transaction(<<~SQL)
+  update reading_statuses
+  set status = 'abandoned'
+  where started_at < (now() - '2 years'::interval)
+    and finished_at is null;
+SQL
+```
+
+You might imagine then that we can put multiple heredocs in a method call. That
+leads to [_stacked
+heredocs_](https://www.visualmode.dev/ruby-operators/heredoc#stacked-heredocs).
+
+```ruby
+execute_in_transaction(<<~SQL1, <<~SQL2, <<~SQL3)
+  update reading_statuses
+  set status = 'abandoned'
+  where started_at < (now() - '2 years'::interval)
+    and finished_at is null;
+SQL1
+  insert into activity_log (name, description)
+  values ('abandon_books', 'Mark unread books as abandoned');
+SQL2
+  delete from background_jobs
+  where id = #{job_id}; -- better to sanitize values like this
+SQL3
+```
+
+Notice we terminate the body of each heredoc with its closing identifier and
+immediately begin the body of the next one.

unix/type-fewer-paths-with-brace-expansion.md

@@ -0,0 +1,49 @@
+# Type Fewer Paths With Brace Expansion
+
+Bash has a feature called _brace expansion_ that allows us to do a kind of
+shorthand when writing out file paths. We can specify multiple variants
+comma-separated between curly braces and they'll each be expanded into separate
+arguments.
+
+It's easier to understand this by seeing it. If we type the following (don't
+hit `Enter` yet):
+
+```bash
+$ mkdir src/{one,two,three}
+```
+
+And then hit _Tab_:
+
+```bash
+$ mkdir src/one src/two src/three
+```
+
+Bash uses the portion in braces to expand into separate arguments. The part
+outside the braces gets reused for each. That's where we get some savings from
+typing out the same path each time.
+
+Here is another example where we use `mv` to rename a file deeply nested in our
+project:
+
+```bash
+$ mv projects/project1/src/app/utils/{names,constants}.js
+```
+
+We don't even have to _Tab_ it out. We can hit _Enter_ directly and `mv` gets
+both arguments.
+
+Similarly, how about we change the extension of our renamed file:
+
+```bash
+$ mv projects/project1/src/app/utils/constants.{js,ts}
+```
+
+I've always found this feature most useful with paths and filenames, but you
+can do brace expansion with any arguments.
+
+```bash
+$ echo 1{3,1,6,4,9,2,7,5}
+13 11 16 14 19 12 17 15
+```
+
+[source](https://www.gnu.org/software/bash/manual/html_node/Brace-Expansion.html)

workflow/convert-an-epub-document-to-pdf-on-mac.md

@@ -6,7 +6,7 @@ convert it using the `ebook-convert` binary from `Calibre`.
 First, install `Calibre`:
 
 ```bash
-$ brew cask install calibre
+$ brew install --cask calibre
 ```
 
 Then convert your ePub using `ebook-convert`: