FileExists reports whether the named file or directory exists.

GrepFile like command grep -E for example: GrepFile(`^hello`, "hello.txt") \n is striped while read.

NewEMail create new Email struct with config json.

RandomCreateBytes generate random []byte by specify chars.

SearchFile Search a file in paths.

SelfDir gets compiled executable file directory.

SelfPath gets compiled executable file absolute path.

Attachment is a struct representing an email attachment.

Email is the type used for email messages.