How can I add a newline (in each row of a text file) exactly three characters after a certain character(comma in this case)?

Question

I have a file with country, city and state info, among other information. The content of the file looks something like this: (only the part pertaining to the question shown)

Some lines (rows) of text
...
United States
Memphis, TN 38116-3252
...
More lines of text
...
United States
Austin, TX 78726
...

What I would like to do is add a newline before the zip code or after TN (for example) and also replace the ',' with a newline. But I'm assuming the second part will be easier.

Desired format:

Some lines (rows) of text
...
United States
Memphis
TN
38116-3252
...
More lines of text
...
United States
Austin
TX
78726
...

The end goal is to import the data into a spreadsheet like:

Some info | Country | State | City | Etc.
abc       | United..| Texas | Austi| zcx

I'm open for anything that works sed, awk, etc.

Answer 1

I would use sed for this:

sed -E 's/, /\n/;s/([A-Z]{2}) /\1\n/' States  
Some lines (rows) of text
...
United States
Memphis
TN
38116-3252
...
More lines of text
...
United States
Austin
TX
78726

The first expression s/, /\n/ searches for a comma followed by a space and replaces with newline.

The second expression s/([A-Z]{2}) /\1\n/ searches for any two uppercase letters followed by a space, and replaces with those letters followed by a newline.

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sed --version
sed (GNU sed) 4.2.2