Заменить номером строки в определенной строке текстового файла

gawk '{gsub(/,/,"|"); printf("%s", $0 RT)}' RS='"[^"]*"' input.txt

или то же самое, но по-другому:

gawk -F, '{$1=$1; printf("%s", $0 RT)}' RS='"[^"]*"' OFS='|' input.txt

Вход

John,Tonny,"345.3435,23",56th Street
one,"two,three",four,five,"six,stub,seven",eight,nine
one,"two,three",four,five,"six,stub,seven",eight,nine,"ten,eleven,twelve"

Выход

John|Tonny|"345.3435,23"|56th Street
one|"two,three"|four|five|"six,stub,seven"|eight|nine
one|"two,three"|four|five|"six,stub,seven"|eight|nine|"ten,eleven,twelve"