A *complete* listing of operators in Nix, and their predence.

This article was originally published at https://gist.github.com/joepie91/c3c047f3406aea9ec65eebce2ffd449d.

The information in this article has since been absorbed into the official Nix manual. It is kept here for posterity. It may be outdated by the time you read this.

Lower precedence means a stronger binding; ie. this list is sorted from strongest to weakest binding, and in the case of equal precedence between two operators, the associativity decides the binding.

Prec	Abbreviation	Example	Assoc	Description
1	SELECT	e . attrpath [or def]	none	Select attribute denoted by the attribute path attrpath from set e. (An attribute path is a dot-separated list of attribute names.) If the attribute doesn’t exist, return default if provided, otherwise abort evaluation.
2	APP	e1 e2	left	Call function e1 with argument e2.
3	NEG	-e	none	Numeric negation.
4	HAS_ATTR	e ? attrpath	none	Test whether set e contains the attribute denoted by attrpath; return true or false.
5	CONCAT	e1 ++ e2	right	List concatenation.
6	MUL	e1 * e2	left	Numeric multiplication.
6	DIV	e1 / e2	left	Numeric division.
7	ADD	e1 + e2	left	Numeric addition, or string concatenation.
7	SUB	e1 - e2	left	Numeric subtraction.
8	NOT	!e	left	Boolean negation.
9	UPDATE	e1 // e2	right	Return a set consisting of the attributes in e1 and e2 (with the latter taking precedence over the former in case of equally named attributes).
10	LT	e1 < e2	left	Less than.
10	LTE	e1 <= e2	left	Less than or equal.
10	GT	e1 > e2	left	Greater than.
10	GTE	e1 >= e2	left	Greater than or equal.
11	EQ	e1 == e2	none	Equality.
11	NEQ	e1 != e2	none	Inequality.
12	AND	e1 && e2	left	Logical AND.
13	OR	e1 || e2	left	Logical OR.
14	IMPL	e1 -> e2	none	Logical implication (equivalent to !e1 || e2).