Tweak descriptions of ruby examples

sheets/ruby

@@ -1,26 +1,27 @@
-# Ruby is a dynamic, reflective, object-oriented, general-purpose programming language
-# ruby is a ruby interpreter
+# ruby
+# Interpreter of object-oriented scripting language Ruby
 
-# invoke Ruby from the command line to run the script foo.rb
+# Invoke Ruby; a dynamic, reflective, object-oriented, general-purpose
+# programming language; from the command line to run the provided script.
 ruby foo.rb
 
-# pass code as an argument
+# Execute Ruby code directly from the command-line.
 ruby -e 'puts "Hello world"'
 
-# The -n switch acts as though the code you pass to Ruby was wrapped in the following:
-# while gets
-#   # code here
-# end
+# The `-n` switch allows Ruby to execute code within a `while gets` loop.
 ruby -ne 'puts $_' file.txt
 
-# Beware that with the -n switch $_ contains newline character in the end.
-# With the addition of -l switch each line read has the newline character removed.
+# Beware that with the `-n` switch, `$_` contains newline character at the end.
+# With the addition of the `-l` switch, each line read has the aforementioned
+# newline character removed.
 ls | ruby -lne 'File.rename($_, $_.upcase)'
 
-# The -p switch acts similarly to -n, in that it loops over each of the lines in the input
-# after your code has finished, it always prints the value of $_
-# Example: replace e with a
+# The `-p` switch acts similarly to `-n`, in that it loops over each of the
+# lines in the input, after your code has finished; it always prints the value
+# of `$_`.
+#
+# The following example replaces `e` with `a`.
 echo "eats, shoots, and leaves" | ruby -pe '$_.gsub!("e", "a")'
 
-# BEGIN block executed before the loop
+# BEGIN block executed before the loop.
 echo "foo\nbar\nbaz" | ruby -ne 'BEGIN { i = 1 }; puts "#{i} #{$_}"; i += 1'