Merge 295fe153ad into 02086e7115

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).
 
-_1453 TILs and counting..._
+_1455 TILs and counting..._
 
 ---
 
@@ -80,6 +80,7 @@ _1453 TILs and counting..._
 * [XState](#xstate)
 * [YAML](#yaml)
 * [Zod](#zod)
+* [Zsh](#zsh)
 
 ---
 
@@ -1726,6 +1727,11 @@ _1453 TILs and counting..._
 - [Incorporate Existing Type Into Zod Schema](zod/incorporate-existing-type-into-zod-schema.md)
 - [Set Custom Error Message For Nonempty Array](zod/set-custom-error-message-for-nonempty-array.md)
 
+### Zsh
+
+- [Add To The Path Via Path Array](zsh/add-to-the-path-via-path-array.md)
+- [Link A Scalar To An Array](zsh/link-a-scalar-to-an-array.md)
+
 ## Usage
 
 The `.vimrc` file for this project contains a function `CountTILs` that can

zsh/add-to-the-path-via-path-array.md

@@ -0,0 +1,25 @@
+# Add To Path Via Path Array
+
+Typically when managing what is on your path in a Unix shell environment, you
+override the `PATH` environment variable with `export`. This is usually an
+append or prepend to bring along the existing path entries.
+
+```bash
+$ export PATH="$PATH:/Users/me/.local/bin"
+```
+
+The `zsh` shell environment exposes another way of adding to your path. They
+have a `path` array which can be a little easier to work with since you can use
+an array operation instead of string interpolation.
+
+Here is how we'd do the same as above:
+
+```bash
+$ path+=/Users/me/.local/bin
+```
+
+This works because there is an automatic linking in zsh between arrays and
+colon-separated strings (_scalars_).
+[source](https://www.zsh.org/mla/users//2005/msg01132.html)
+
+[source](https://superuser.com/a/1447959)

zsh/link-a-scalar-to-an-array.md

@@ -0,0 +1,38 @@
+# Link A Scalar To An Array
+
+`Zsh` has a builtin command `typeset` that does a variety of things. When given
+the `-T` flag and the names of a scalar and an array, it will link them
+together so that a change to one is reflected in the other.
+
+The scalar is a string of values delimited by a colon (`:`). The array is an
+array that can be interacted with using array operations like append (`+=`).
+
+```bash
+$ typeset -T FOO foo
+
+$ echo $FOO
+
+
+$ export FOO="one:two"
+
+$ echo $foo
+one two
+
+$ foo+=three
+
+$ echo $FOO
+one:two:three
+```
+
+Notice `FOO` is initially empty. I then `export` it to overwrite it with two
+values delimited by a colon. Since `foo` is automatically kept in sync, I can
+`echo $foo` and see those values displayed as an array. I can then append a
+third value using an array operation on `foo`. The update will be automatically
+reflected in `FOO`.
+
+`Zsh` does this under the hood for `PATH` and `path` which is why you can [add
+to the path via the path array](add-to-the-path-via-path-array.md).
+
+See `man zshbuiltins` for more details.
+
+[source](http://devlib.symbian.slions.net/s3/GUID-D87C96CE-3F23-552D-927C-B6A1D61691BF.html)