Is there a program that functions like printf with an entire file as input?

My use case is as follows.

file.txt

First arg: %s
Second %s arg,
Third %s

Run prog file.txt "one" "$(ls dir1/dir2)" "three"

Resulting in

First arg: one
Second file1 file2 file3 arg,
Third three

I first thought to use sed but that inevitably runs into problems when bash substitutions get read as format characters like this sed s/%1/$VAR/g -> sed s/%1/dir1/dir2/file1/g

I’m thinking I could iterate by lines and take the text before and after a substitute and just insert like

FIRST=$(sed "s/%s.*//" <<< $LINE)
SECND=$(sed "s/.*%s//" <<< $LINE)

echo "$FIRST $SUB $SECND"

Though that’s limited to one sub per line and I would prefer a cleaner solution if it exists.

Answer

You could use printf with the whole file as the formatting string:

printf "$(< file.txt)n" one two three

Notice that command substitution removes trailing newlines, so a separate n is added back; see How to avoid bash command substitution to remove the newline character? for details.