From man csh:
$< Substitutes a line from the standard input, with no further
interpretation thereafter. It can be used to read from the
keyboard in a shell script. (+) While csh always quotes $<, as
if it were equivalent to `$<:q', tcsh does not. Furthermore,
when tcsh is waiting for a line to be typed the user may type
an interrupt to interrupt the sequence into which the line is
to be substituted, but csh does not allow this.