一個有用的Unix重定向

1、fx# cat > test.txt
I have a good idea!
And you?
fx# cat test.txt
I have a good idea!
And you?
fx#
---實現要求：在?後新開一行，按ctrl+D。必須是在行首的^D才有效。
2、fx# cat > test.txt < ? I have a Good Idea!
? And You?
? NO.
? GO!
fx# cat test.txt
I have a Good Idea!
And You?
NO.
fx#
---實現要求：必須在行首的，符合<<後面的字符，等於結束字符。