Assignment is a statement in most languages in which a a value is associated with an identifier within the active binding environment.
Such bindings may be immutable such that the value associated with an identifier cannot be changed after initial assignment, or as an extension some languages rely entirely upon nested binding environments and corresponding argument passing rather than standalone statements.
Assignments in bash take the form
<IDENTIFIER>=<VALUE>with the specific notes that there must not be any spaces to either
side of the =, and the value may be quoted or contain
escapes if it has spaces or other characters that may be otherwise
parsed.
Assignments in Lilypond conform to standard =
syntax:
<identifier> = <expression>