Add lines of a list as prefixes in filenames

How about

mapfile -t list < list.txt

i=0
for f in *.gf; do 
  echo mv "$f" "${list[i++]}_$f"
done

Remove the echo once you are happy that it is doing the right thing.

With POSIX sh syntax:

#! /bin/sh -
for f in *.gf; do
  IFS= read -r line <&3 || break
  mv -i -- "$f" "${line}_$f"
done 3< list.txt

Globbing (here *.gf) sorts the list of files lexically (as per the locale's collation order in modern and POSIX compliant shells).

Related