LFCS: Linux Foundation Certified System AdministratorDemo

In shell scripting, backticks (or $(...)) perform command substitution, executing the enclosed command and substituting its output. Therefore actdat=date`` runs the date command and assigns its output (the current date/time string) to the variable actdat. The other options either assign a literal string ('date'), use invalid syntax for variable assignment (set, pipe), or redirect output to a file rather than storing it in a variable.