In addition to what Scott has already said...

There are two things that are special about a filename starting with a period.

The ls command (without the -a option and without a filename pattern given as an operand that explicitly names the file) will not include those files in its output. (That is why files with names whose first character is a period are sometimes called hidden files.)

And, in the shell, filename matching patterns that do not begin with a period will not match a filename that has a first character that is a period. For example, if I am in a directory that contains the files ., .., .hidden, abc, and xyz, then the command ls will produce the output:

Code:

abc	xyz

the command ls -a will produce the output:

Code:

.	..	.hidden	abc	xyz

the command echo * will produce the output:

Code:

abc xyz

the command echo .* will produce the output:

Code:

. .. .hidden

and the command echo * .* will produce the output:

Code:

abc xyz . .. .hidden