There are some files that are not listed by the ordinary ls command. These files have names beginning with the character . (called "dot"), such as .cshrc, .login and .profile. Use the ls -a command to list these dot files:
$ ls -a . .. .cshrc .login .profile emptyfile
Notice that the files beginning with . are listed before the other files. There are two special files in this listing: the file .is the reference for the current directory, and the file .. is the reference for the parent directory.
Generally speaking, files that begin with . are used by system utilities and are not usually modified by the user. There are a few exceptions to this.