How can I add a comma at the end of every line except the last line?

Question

I want add a comma at the end of every line of this kind of file except the last line:

I have this now:

{...}
{...}
{...}
{...}

I w

Answer 1

You can use something like this:

 sed 's/$/,/' file.txt > file_with_added_commas.txt

This will substitute the end of the line with a ',' and write it to file_with_added_commas.txt

For more information refer to: add text at the end of each line