The dot character

The dot character matches any character except the new line (\n). Let's use it against the following file:

Welcome to shell scripting.
I love shell scripting.
shell scripting is awesome.

Say we use the following commands:

$ awk '/.sh/{print $0}' myfile
$ sed -n '/.sh/p' myfile

This pattern matches any line containing sh and any text before it:

As you can see, it matches the first two lines only because the third line starts with sh, so no match for the third line.