starts a here-document. A here-document is a type of input redirection of a text block. The contents of the here-document is ended when
TAG is encountered on a line by itself. For example:
The tag can be any word, and in your case, the word is
simple.sh, and the shell complains that it can't find the word that would end the here-document.
What I presume you meant is
cat simple.sh | grep ... >>Result
cat <simple.sh | grep ... >>Result
grep ... simple.sh >>Result
Also note that the regular expression
^[^abc]$.*!$ can never match as there is no single line with a
! after the end of the line.