Overview

Jawk is a pure Java implementation of AWK^[1]. You can run AWK programs in a JVM application and integrate with your Java code:

$ echo "hello world" | java -jar jawk-7.0.01-standalone.jar '{ print $2 ", " $1 "!" }'
world, hello!

Awk awk = new Awk();
String result = awk.script("{ print toupper($0) }").input("hello world").execute();
// result = "HELLO WORLD\n"

Compatibility and Compliance

The above scores are calculated from the latest compatibility tests during mvn verify site. See the full compatibility dashboard^[2] for per-suite maps and the Failsafe report^[3] for detailed test results.

Key Capabilities

• CLI-compatible AWK execution with inline scripts, script files, operands, and input files
• Java entry points for script execution, expression evaluation, tuple compilation, and repeated reuse
• Structured input through InputSource for row-oriented or already-tokenized data
• Gawk builtins enabled by default: asort(), asorti(), typeof(), isarray(), mkbool(), gensub(), patsplit(), strtonum(), systime(), mktime(), strftime(), the gettext functions, and PROCINFO["sorted_in"]
• Explicit extension loading through the Java API or the CLI
• Tuple serialization for CLI precompilation and later loading
• Sandbox-specific tuples and runtime components through SandboxedAwk

Differences with Traditional AWK

Jawk aims to be a practical AWK implementation for JVM environments, but it is not a byte-for-byte clone of every historical AWK behavior. Some differences are deliberate and come from the way Jawk integrates with Java:

• Regular expression behavior follows Java's regex engine, which may differ from traditional AWK regexes in edge cases. Notably, alternation picks the first matching branch rather than the POSIX longest one, which can affect match(), field splitting with patsplit(), and similar content-driven matching: order alternatives longest-first.
• printf() and sprintf() try to replicate C-style formatting but may have differences due to Java's formatting capabilities and limitations.
• Some floating-point edge cases may differ due to Java's handling of floating-point arithmetic and representation.
• Jawk resolves user-defined function calls during compilation. It does not defer all of that work to runtime.
• The date and time functions (mktime(), strftime()) follow the Java platform's time zone data and calendar rules rather than the C library's, which differs from gawk in a few edge cases.

The Compatibility^[2] page details these edge cases, along with the places where Jawk deliberately follows gawk rather than historical AWK, and the live compatibility reports.

History of Jawk

Next Steps

• Install Jawk^[17]
• Embed Jawk in Java^[18]
• Learn the CLI^[19]
• Work with variables and arguments^[20]
• Work with structured input^[21]
• Compile, evaluate, and reuse tuples^[22]
• Load or write extensions^[23]