Question

I have a file which has contents on every line following this format (A, B, C, and D represent text):

A B [C] D

E.g.:

cat Cat [noun] This animal likes to eat mice.

• The first separator is the first occurrence of a space (” “) on a line.
• The second separator is the first occurrence of a space followed by a square opening bracket (” [“).
• The final separator is the first occurrence of a square closing bracket followed by a space (“] “).

I want to convert all of the content in this file to a CSV file, where @ is used in place of commas:

A@B@C@D

• The original file contains many foreign characters in UTF-8.
• There are no spaces or brackets within the contents of A and B.
• C sometimes contains spaces, but no brackets inside the two given.
• D contains anything from spaces, square brackets, etc. and the contents should remain unchanged by the conversion.

How can I convert this file to that format?

Answer 1

You need to perform char substitution. I suggest you use sed with regular expression. This is a piece of code corresponding to your example:

sed -r 's/( |\[|\])+/@/g' file_to_modify.txt > file_for_output.txt

For substituting every column in a specific way, the following form is used:

sed -r 's/([^ ]+) ([^ ]+) \[([^]]+)] (.*$)/\1@\2@\3@\4/g' f1.txt > f2.txt