convert cert or key to single line with \n included

gistfile1.txt

awk '{sub(/\r$/,""); printf "%s\\n", $0}' filename

This command reads a file line by line and converts it into a single, long string, using the literal characters \n as a separator.

It does two main things for every line it reads:

It Cleans: The sub(/\r$/,"") part finds and removes the invisible Windows "carriage return" character (\r) from the end of the line. If a line is already clean, this part does nothing.

It Joins: The printf "%s\\n", $0 part prints the cleaned line, followed immediately by the text \n. Because printf doesn't add a line break, all the lines get joined together into one.