using dd writing iso file to usb drive

[Daniel Crone]

When writing an image file to a usb drive, first I changed to the directory where the file was, and then I was typing the dd command in this form.
sudo dd if=filename.iso of=/dev/sdf bs=4M conv=sync
The file name was long, so after the first few letters, I used the tab key.
But nothing happened.
Should the name have been filled in?
The name of the file was the only one in the Downloads directory.