is there a one-line command/script to copy one file to many files on linux?
cp file1 file2 file3
cp file1 file2 ; cp file1 file3
count as a "one-line command/script"? How about
for file in file2 file3 ; do cp file1 "$file" ; done
Or, for a slightly looser sense of "copy":
tee <file1 file2 file3 >/dev/null