Add Execute Several Commands With Backtick Heredoc as a Ruby TIL

ruby/execute-several-commands-with-backtick-heredoc.md

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+# Execute Several Commands With Backtick Heredoc
+
+A fun feature of Ruby is that we can execute a command in a subprocess just by
+wrapping it in backticks.
+
+For instance, we might shell out to `git` to check if a file is tracked:
+
+```ruby
+`git ls-files --error-unmatch #{file_path} 2>/dev/null`
+$?.success?
+```
+
+But what if we need to execute several commands? Perhaps they depend on one
+another. We want them to run in the same subprocess.
+
+For this, we can use the backtick version of a heredoc. That is a special
+version of a heredoc where the delimiter is wrapped in backticks.
+
+```ruby
+puts <<`SHELL`
+  # Set up trap
+  trap 'echo "Cleaning up temp files"; rm -f *.tmp' EXIT
+  
+  # Create temporary file
+  echo "test data" > work.tmp
+  
+  # Do some work
+  cat work.tmp
+  
+  # Trap will clean up on exit
+SHELL
+```
+
+Here we set up a `trap` for file cleanup on exit, then create a file, then do
+something with the file, and that's it, the process exits (triggering the
+trap).
+
+[source](https://ruby-doc.org/3.3.6/syntax/literals_rdoc.html#label-Here+Document+Literals)