I have a text file containing strings in each line like this:
'abc',
'dog',
'zebra',
I want to make it like:
'abc', 'abc',
'dog', 'dog',
'zebra', 'zebra',
How best to do it in bash?
1 Answer
You could call sed:
sed -r 's/(.*)/\1 \1/' dupcol.csv
The .* says to match any character on a line, repeatedly. The ( ) around it says to store the match in the first register (\1). Then the full match is output twice.
I just usually default to using sed’s -r option to make for cleaner (extended) regexes. However, omitting the -r enables & to match the full pattern. So a simpler version of this special case where you want to keep the full match is:
sed -r 's/.*/& &/' dupcol.csv
If you want to change the file in-place, add the -i option.
3 Comments
Jand
Worked like a charm. Thanks. Would be more informative if you also explain what
\1 \1 does.
123
As you are using everything matched you can just use
& without any capture groups or need for -r. sed 's/.*/& &/'
Micah Elliott
Awesome tip on &. I had originally tried that but now see that it does not work with -r. I've added this into the answer. Thanks!
paste -d " " dupcol.csv dupcol.csv