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

assuming you don't want to change header and assuming you don't have embedded tabs

# cat file
header  header  header
one     two     three

$ awk 'NR>1{$1=$1}1' OFS="," file
header  header  header
one,two,three

NR>1 skips the first header. you mentioned you know how many lines of header, so use the correct number for your own case. with this, you also do not need to call any other external commands. just one awk command does the job.

another way if you have blank columns and you care about that.

awk 'NR>1{gsub("\t",",")}1' file

using sed

sed '2,$y/\t/,/' file #skip 1 line header and translate (same as tr)