read -r -p "Enter key to fetch: " key
awk -vk="$key" -F"=" '$1~k{ print "value for "k" is "$2} ' file
выход
$ ./shell.sh
Enter key to fetch: key1
value for key1 is value1
или вы можете просто использовать оболочку (например, bash)
read -r -p "Enter key to fetch: " key
while IFS="=" read -r k v
do
case "$k" in
*"$key"* ) echo "value of key: $k is $v";;
esac
done <"file"