how to read line by line from file in bash script?

Question

I've searched online about this problem and I've found two ways so far:

   while read line; do
      commands
   done < "$filename"

and

    for $line in $(cat $filename); do
       commands
    done

none of these work if the lines have a space though, for example if we have a line like that

  textextext text

it won't print textextext text

but

  textextext
  text

it counts these things as a different line, how can I avoid this to happen?

Answer 1

Like this?

while IFS= read line ; do
   something "$line"
done <"$file"

Here is a brief test:

while IFS= read line ; do echo "$line"; done <<<"$(echo -e "a b\nc d")"
a b
c d