$ sudo mount -t cifs -o username=myname,password=mypassword //mydomain/share/Users/me /mnt/mydir
# Success
$ printf "username=mynamenpassword=mypasswordn" >> mycreds
$ sudo mount -t cifs -o credentials=mycreds //mydomain/share/Users/me /mnt/mydir
# error 2 (No such file or directory) opening credential file mycreds

$ ls -l mycreds
# -rwSr-xr-x. 1 root root 40 Mar 19 18:23 mycreds