How to make URL's out of this text with least resources?

Question

INPUT:

nyeeeeeeeeeeeeeee.txt:sadfsadf
sadjflsajfd:jasdlfjalsfd
foo/asdfsafd.txt:laksjdlfajsfd

OUTPUT:

<a href="nyeeeeeeeeeeeeeee.txt">nyeeeeeeeeeeeeeee.txt</a>:sadfsadf
<a href="sadjflsajfd">sadjflsajfd</a>:jasdlfjalsfd
<a href="foo/asdfsafd.txt">foo/asdfsafd.txt</a>:laksjdlfajsfd

So I need to convert the INPUT to OUTPUT, the difference is that OUTPUT is "clickable" because this is in a HTML file.

Q: How can I do this with awk, sed or perl?

I know I can do a "read line by line", but what is the most resource efficient way to do this? (I only need 1 solution, not for all sed/awk/etc.) : is the delimiter.

Answer 1

Strictly what you asked for:

sed 's/\([^:]\+\)/<a href="\1">\1<\/a>/' input.txt

awk -F ':' -vOFS=':' '$1="<a href=\""$1"\">"$1"</a>"' input.txt

while IFS=':' read -r url text; do echo "<a href=\"$url\">$url</a>:$text"; done < input.txt

But for real HTML generating you also have to take care of HTML encoding:

perl -MHTML::Entities -pe 's!([^:]+)(.*)!"<a href=\"".($t=encode_entities($1))."\">$t".encode_entities($2)!e' input.txt