What's wrong with those lines? Both use for the files ( .aliases , login.log ), assuming the files are in the home directory. Those lines won't work when you start a from somewhere besides your home directory, because your files .cshrc or ENV (like .kshrc ) are read whenever a shell starts. If you ever use the to read the .profile and .login from outside your home directory, you'll have the same problem.
Use absolute pathnames instead. As article
explains, the pathname of your home directory is in the tilde
source ~/.aliases echo "Logged in at `date`" >> ~/login.log