fastest way convert tab-delimited file to csv in linux

Question

I have a tab-delimited file that has over 200 million lines. What\'s the fastest way in linux to convert this to a csv file? This file does have multiple lines of header i

Answer 1

the following awk oneliner supports quoting + quote-escaping

printf "flop\tflap\"" | awk -F '\t' '{ gsub(/"/,"\"\"\"",$i); for(i = 1; i <= NF; i++) { printf "\"%s\"",$i; if( i < NF ) printf "," }; printf "\n" }'

gives

"flop","flap""""