Cron Expression Shape Regex

Developer

Regular expression

/^\S+\s+\S+\s+\S+\s+\S+\s+\S+$/

Pattern breakdown

Part	Meaning
`Anchor or context`	Use anchors when you need whole-string validation.
`Main token`	The core token sequence describes the accepted text shape.
`Character class`	Character classes limit which characters are valid.
`Quantifier`	Quantifiers control how many characters or groups are accepted.
`Flags`	Use language-specific flags such as i, m, or u only when needed.

Should match

0 8 * * 1-5
08**1-5

Should not match

0 8 *
not matching sample
0 8 * * 1-5 invalid
0 8 *0 8 * * 1-5

Test cases

Input	Expected	Why it matters
`0 8 * * 1-5`	Match	Representative valid input for this pattern.
`08**1-5`	Match	Representative valid input for this pattern.
`0 8 *`	No match	Common invalid or boundary input.
`(empty string)`	No match	Common invalid or boundary input.
`not matching sample`	No match	Common invalid or boundary input.
`0 8 * * 1-5 invalid`	No match	Common invalid or boundary input.
`0 8 0 8 * 1-5`	No match	Common invalid or boundary input.

JavaScript

const re = /^\S+\s+\S+\s+\S+\s+\S+\s+\S+$/;
re.test(input);

Python

import re
bool(re.search(r"^\S+\s+\S+\s+\S+\s+\S+\s+\S+$", text))

PHP

$ok = preg_match('/^\S+\s+\S+\s+\S+\s+\S+\s+\S+$/', $value) === 1;

Java

Pattern pattern = Pattern.compile("^\\S+\\s+\\S+\\s+\\S+\\s+\\S+\\s+\\S+$");
pattern.matcher(value).find();

Go

re := regexp.MustCompile(`^\S+\s+\S+\s+\S+\s+\S+\s+\S+$`)
ok := re.MatchString(value)

Notes and production use

Cron Expression Shape regex is useful as a practical starting point. Test it against your real input, avoid using it as the only security control, and prefer a parser when the format has complex grammar.

Performance tip: avoid running complex regular expressions repeatedly on very large untrusted strings without limits. Prefer anchored validation patterns, cap input length before matching, and use a parser when the target format has nested grammar.

Cron Expression Shape