Add Exit A Process With An Error Message as a Ruby til

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).
 
-_1194 TILs and counting..._
+_1195 TILs and counting..._
 
 ---
 
@@ -948,6 +948,7 @@ _1194 TILs and counting..._
 - [Enumerate A Pairing Of Every Two Sequential Items](ruby/enumerate-a-pairing-of-every-two-sequential-items.md)
 - [Evaluating One-Off Commands](ruby/evaluating-one-off-commands.md)
 - [Exclude Values From An Array](ruby/exclude-values-from-an-array.md)
+- [Exit A Process With An Error Message](ruby/exit-a-process-with-an-error-message.md)
 - [Expect A Method To Be Called And Actually Call It](ruby/expect-a-method-to-be-called-and-actually-call-it.md)
 - [Extract A Column Of Data From A CSV File](ruby/extract-a-column-of-data-from-a-csv-file.md)
 - [FactoryGirl Sequences](ruby/factory-girl-sequences.md)

ruby/exit-a-process-with-an-error-message.md

@@ -0,0 +1,34 @@
+# Exit A Process With An Error Message
+
+If you want to exit a Ruby process with an unsuccessful error code like `1`,
+you can use
+[`Kernel.exit`](https://ruby-doc.org/core-3.1.2/Kernel.html#method-i-exit).
+
+```ruby
+if arg_is_missing?
+  exit 1
+end
+```
+
+The non-zero status code means this will work great in a scripting scenario,
+like `ruby script.rb && echo 'success'`. If the script has to exit early, it
+won't print 'success'.
+
+That's fine, but it doesn't give the program a chance to tell us _why_ the
+program exited early.
+
+`Kernel` has another method
+[`abort`](https://ruby-doc.org/core-3.1.2/Kernel.html#method-i-abort) that does
+the same thing as `exit 1` while also printing a message to `STDERR`.
+
+```ruby
+if arg_is_missing?
+  abort 'The missing argument must be supplied'
+end
+```
+
+This is handy if you want to communicate more than just the error code. The
+program still exits early with an error code of `1`. And it prints that message
+to `STDERR`.
+
+[source](https://stackoverflow.com/a/23340693/535590)