Logsflags: g

Log4j Pattern Layout Token

Match Log4j / Logback PatternLayout conversion specifiers like `%d{yyyy-MM-dd}`, `%-5p`, or `%c{1}`.

Try it in RegexPro →

Available in

JSSupported

JavaScript / ECMAScript

Browser-native RegExp. Default if you don't pick.

PYSupported

Python (re)

CPython stdlib `re`. Unicode-aware `\w` and `\d` by default.

GOSupported

Go (RE2)

Linear-time matching. No backreferences or lookarounds.

Pattern

regexengine-agnostic

%(?:-?\d+)?(?:\.\d+)?[a-zA-Z](?:\{[^}]*\})?   (flags: g)

Raw source: %(?:-?\d+)?(?:\.\d+)?[a-zA-Z](?:\{[^}]*\})?

How it works

% starts a conversion specifier. (?:-?\d+)? optionally matches a width modifier (negative for left-justify). (?:\.\d+)? optionally matches a max-width. [a-zA-Z] captures the conversion letter (d=date, p=priority, c=category, m=message, n=newline, etc.). (?:\{[^}]*\})? optionally matches a parameter in braces.