Ruby is a surprisingly simple language. Metaprogramming in ruby is a pretty good book that makes it clear what is happening under the hood.
The yield is probably the most complicated part of it, but it is extremely useful for hiding complexity. Once you understand yield, there is very little magic to what ruby is doing.
I prefer python to ruby, but the concept is the same:
As for understanding the command line/reasoning about it, they are usually generated iteratively.
Look at a file to see what you have to work with:
$ cat $file | head -n 5
Decide commas aren't useful and remove them
$ cat $file | sed 's/,//g' | head -n 5
Decide you want a tab between every 4 characters on any given line
$ cat $file | sed 's/,//g' | sed 's/\(....\)/\1\t/g' | head -n 5
Each step of the way you see the output, and every additional pipe modifies the last seen output.
Everything else is just being aware of what tools you can use (sed/awk/grep/xargs/etc) and the limits of the data you work with.
GP may have done something like popping the ruby repl, irb, and then:
The yield is probably the most complicated part of it, but it is extremely useful for hiding complexity. Once you understand yield, there is very little magic to what ruby is doing.
I prefer python to ruby, but the concept is the same:
https://realpython.com/introduction-to-python-generators/
As for understanding the command line/reasoning about it, they are usually generated iteratively.
Each step of the way you see the output, and every additional pipe modifies the last seen output.Everything else is just being aware of what tools you can use (sed/awk/grep/xargs/etc) and the limits of the data you work with.
GP may have done something like popping the ruby repl, irb, and then: