shell-prompt-pattern

shell-prompt-pattern is a variable defined in `shell.el'.
Its value is

"^[^#$%>
]*[#$%>] *"

Documentation:
Regexp to match prompts in the inferior shell.
Defaults to "^[^#$%>\n]*[#$%>] *", which works pretty well.
This variable is used to initialize `comint-prompt-regexp' in the
shell buffer.

If `comint-use-prompt-regexp' is nil, then this variable is only used
to determine paragraph boundaries. See Info node `Shell Prompts' for
how Shell mode treats paragraphs.

The pattern should probably not match more than one line. If it does,
Shell mode may become confused trying to distinguish prompt from input
on lines which don't start with a prompt.

You can customize this variable.