Jawk

Jawk is a pure Java implementation of AWK. You can run it as a CLI, embed it directly in Java applications, compile scripts to reusable tuples, evaluate AWK expressions, feed it structured input, load extensions explicitly, and enable a sandboxed runtime when you need tighter execution constraints.

Support for POSIX AWK and Gawk

Jawk fully implements POSIX AWK, and adds support for the most commonly used gawk-specific features:

• Builtins, available by default through the built-in GNU Awk compatibility extension: asort(), asorti(), typeof(), isarray(), mkbool(), gensub(), patsplit(), strtonum(), systime(), mktime(), strftime(), bindtextdomain(), dcgettext(), dcngettext(), and PROCINFO["sorted_in"]-controlled array traversal
• Arrays of arrays (a[i][j]) and typed regexp literals (@/re/)
• BEGINFILE / ENDFILE special patterns, with the ERRNO and ARGIND special variables, so a script can hook into the command-line file processing loop and skip unreadable files without a fatal error
• The nextfile statement
• The IGNORECASE, SYMTAB, and FUNCTAB special variables

As in gawk, the gawk-specific syntax is not special in --posix mode.

CLI Example

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

The CLI follows the POSIX argument conventions: -- marks the end of options, and the - operand designates standard input as an input file (with FILENAME set to -). As in gawk, once the program text has been supplied (with -f or -L), an unknown option ends option processing and is passed on to the AWK script through ARGV, which makes #! interpreter scripts work. See the CLI documentation for details.

Java Example

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

When writing custom extensions, annotate associative array parameters with @JawkAssocArray and declare them as Map values rather than concrete map implementations.

Java variables passed to embedded Jawk scripts may include Map and List values, including nested JSON-like object trees. Lists are materialized as AWK arrays with zero-based numeric indexes.

Documentation

• Overview: https://jawk.io/index.html
• CLI: https://jawk.io/cli.html
• Java: https://jawk.io/java.html
• Extensions: https://jawk.io/extensions.html
• Writing Extensions: https://jawk.io/extensions-writing.html

Contributing

See CONTRIBUTING.md.