<<
.cat << EOF
Hello
EOF | nl
cat << EOF | nl
Hello
EOF
You have a here document, and appear to have added text after the terminating token.
This is not allowed. If it was meant to continue the command, put it
on the line with the <<
.
If it helps, look at << "END" as if it was < file, and make sure the resulting command is valid. This is what the shell does. You can then append here document data after the command.
None
ShellCheck is a static analysis tool for shell scripts. This page is part of its documentation.