?: Elvis OperatorReturns the right operand if the left operand is falsy (expression)
The Elvis Operator is a little like a conditional where the result of the operation is the first non-falsy value from left to right.
A falsy value is any of the following:
null data typestr or generic with the value false,
null, 0, no, off,
fail, failed, or disablednum, float or int)
with the value 0false» $foo = $bar ?: "baz"If $bar is falsy, then the value of $foo
will be “baz”.
» $unset_variable ?: null ?: false ?: "foobar"
foobarWikipedia explains this best where it says:
The name “Elvis operator” refers to the fact that when its common notation,
?:, is viewed sideways, it resembles an emoticon of Elvis Presley with his signature hairstyle.
err: Print a line to the stderrexpr:
Expressions: mathematical, string comparisons, logical operatorsout: Print a string to the stdout with a trailing new
line charactertrypipe: Checks for non-zero exits of each function in
a pipelinetry:
Handles non-zero exits inside a block of code&& And
Logical Operator: Continues next operation if previous operation
passes?? Null
Coalescing Operator: Returns the right operand if the left operand
is empty / undefined (expression)? stderr Pipe:
Pipes stderr from the left hand command to stdin of the right hand
command (removed 8.0)|| Or Logical
Operator: Continues next operation only if previous operation
failsThis document was generated from gen/expr/elvis-op_doc.yaml.
This site's content is rebuilt automatically from murex's source code after each merge to the master branch. Downloadable murex binaries are also built with the website.
Last built on Mon Feb 2 23:22:37 UTC 2026 against commit 8678ad88678ad89405c2bdd2a92b203f026bc3d46abc88f.
Current version is 7.2.1001 (unknown) which has been verified against tests cases.