Parsing ENV with SED - sed

Question

I have an env file
ENV=development
PORT=3000
SECRET_KEY=-----BEGIN PRIVATE KEY-----\nKEYKEYKEY\n-----END PRIVATE KEY-----\n
How can I parse this file using SED to properly format it?
Used this solution
for line in `cat ${FILE_NAME_ENV}`
do
KEY=$(echo $line | sed 's/=.*//')
VAL=$(echo $line | sed 's/[^=]*=//')
echo $KEY
echo $VAL
done
But SECRET_KEY is splitting over multiple lines due to spaces in the value
ENV
development
PORT
3000
SECRET_KEY
-----BEGIN
PRIVATE
PRIVATE
KEY-----\nKEYKEYKEY\n-----END
KEY-----\nKEYKEYKEY\n-----END
PRIVATE
PRIVATE
KEY-----\n
KEY-----\n
How can i make key value in one line?
SECRET_KEY
-----BEGIN PRIVATE KEY-----\nKEYKEYKEY\n-----END PRIVATE KEY-----\n

Answer 1

Using sed
$ sed -n 's/^\(SECRET_KEY\)=/\1\n/p' input_file
SECRET_KEY
-----BEGIN PRIVATE KEY-----\nKEYKEYKEY\n-----END PRIVATE KEY-----\n

Answer 2

Suggesting to enclose echo command arguments with " to contain each line as single argument to command.
Suggestion 1: fix missing "
for line in "$(cat ${FILE_NAME_ENV})"; do
KEY=$(echo "$line" | sed 's/=.*//')
VAL=$(echo "$line" | sed 's/[^=]*=//')
echo "$KEY"
echo "$VAL"
done
Output 1:
ENV
PORT
SECRET_KEY
development
3000
-----BEGIN PRIVATE KEY-----\nKEYKEYKEY\n-----END PRIVATE KEY-----\n
Suggestion 2: fix with echo -e to accept \n as newline
for line in "$(cat ${FILE_NAME_ENV})"; do
KEY=$(echo "$line" | sed 's/=.*//')
VAL=$(echo "$line" | sed 's/[^=]*=//')
echo "$KEY"
echo -e "$VAL"
done
Output 2:
ENV
PORT
SECRET_KEY
development
3000
-----BEGIN PRIVATE KEY-----
KEYKEYKEY
-----END PRIVATE KEY-----