cat * |  awk 'BEGIN { RS="," } {print $0}' 
cat * |  awk '{ RS="," } {print $0}'
# $0 mean print everything, play with print $1 # $2 when you have more rows 


cat file | awk 'BEGIN { RS="," }1'

https://riptutorial.com/awk/example/11074/rs---record-separator
https://www.unix.com/shell-programming-and-scripting/168415-awk-transpose-csv-row-column.html