Behavior Changes by Version

Unreleased

No user-visible behavior changes recorded yet.

v7.0.01^[2] (2026-07-31)

• print outputs numeric-looking strings verbatim, as POSIX requires: print "0100" now prints 0100 (previously 100), and input-derived values such as $1 keep their original text. OFMT applies only when printing actual non-integral numbers, and CONVFMT governs number-to-string conversion everywhere else (#529^[3]).
• Range patterns (begpat, endpat) evaluate their conditions lazily: the end condition is not evaluated until the range has started, so conditions with side effects behave as in gawk and One True Awk (#115^[4]).
• print (a), (b) parses correctly: a single parenthesized expression followed by a comma continues the output list, a parenthesized group before in is a membership key, and ((i, j) in array) is accepted as an expression (#535^[5]).

v7.0.00^[6] (2026-07-30)

• The full set of gawk language extensions is now enabled by default: BEGINFILE / ENDFILE special rules, the nextfile statement, the ERRNO and ARGIND special variables, @include, @namespace, typed regexp literals (@/re/), indirect function calls (@f()), and gawk-compatible runtime array/scalar typing diagnostics.
• All gawk built-in functions are now implemented: asort(), asorti(), typeof(), isarray(), mkbool(), gensub(), patsplit(), strtonum(), systime(), mktime(), strftime(), bindtextdomain(), dcgettext(), dcngettext(), plus SYMTAB, FUNCTAB, and PROCINFO["sorted_in"]-controlled array traversal. As a consequence, these names are reserved by default and can no longer be used as variables (see Compatibility^[7]).
• The new strict --posix mode disables all gawk extensions when you want the standard and nothing else.
• The CLI handles -- and the - operand per POSIX, and passes unknown options through to the AWK script in ARGV once the program text has been supplied, which makes #! interpreter scripts work as in gawk.

v6.4.01^[8] (2026-06-03)

• Input-derived values (fields, getline results, split() pieces) now follow POSIX “numeric string” (strnum) semantics: they compare numerically when both operands are numeric, and as strings otherwise, matching gawk and One True Awk.

v6.2.00^[9] (2026-05-04)

• New persistent memory support: the --persist <file> CLI option (or the JAWK_PERSISTENT_MEMORY environment variable) saves user-defined global variables to a file and restores them on the next run, in the spirit of gawk's persistent memory feature.

v6.1.00^[10] (2026-04-19)

• gawk-style arrays of arrays (a[i][j]) are now supported.
• New --posix CLI option.

v6.0.00^[11] (2026-04-16)

• Breaking change for Java embedders: the project moved to jawk.io^[12], with new Maven coordinates and the io.jawk package (previously org.metricshub.jawk), and the Java API was overhauled (AwkSink for customized output, InputSource for structured input, and a purely behavioral AwkSettings).
• Fixed print argument list parsing (argument continuation detection).

v5.0.00^[13] (2025-11-04)

• Java embedding API changes only (AssocArray became a real java.util.Map, refined extension metadata APIs); no changes to AWK script behavior.

v4.1.00^[14] (2025-09-29)

• Removed the deprecated Jawk-specific language extensions: the _INTEGER, _DOUBLE, and _STRING typecast keywords (and the -y CLI flag), and the _sleep and _dump keywords (and the -x CLI flag).
• Removed the logging framework: Jawk no longer emits SLF4J messages; runtime warnings go to standard error.
• Environment variables with non-numeric values no longer trigger spurious NumberFormatException log messages.

v4.0.01^[15] (2025-08-08)

• Fixed field splitting with a regex FS producing leading or trailing separators, and a tokenizer regression, raising One True Awk test-suite compatibility from 94.2% to 97.8%.

v4.0.00^[16] (2025-07-29)

A large conformance release aligning Jawk with One True Awk^[17]:

• Statements and control flow: getline without an lvalue, exit code handling, early-exit logic, pattern negation, range (condition pair) evaluation, post-increment/decrement on uninitialized variables and on $ fields, newlines in for loops, and ^= (power assignment).
• Fields and records: dynamic field numbers ($(expr)), NF tracking, FS parsing on empty lines, split() return count and whitespace-regex handling, and SUBSEP handling.
• Output: ternary expressions inside print, print argument handling, pipe output handling and flushing, and ORS flushing.
• Values and arrays: numeric string validation via BigDecimal, numeric detection when printing fields, array iteration in insertion order, array deletion with numeric keys, and array comparison.
• rand() produces a deterministic sequence for a given srand() seed.

v3.3.05^[18] (2025-04-03)

• Java embedders only: packages renamed from org.sentrysoftware.jawk to org.metricshub.jawk; no changes to AWK script behavior.

v3.3.04^[19] (2025-02-13)

• Fixed sub() with dollar references, and sub() / gsub() with & references in the replacement string.

v3.3.03^[20] (2024-08-29)

• Fixed gsub() on array elements.
• Removed the spurious SLF4J connection message from standard output.

v3.3.02^[21] (2024-08-09)

• Fixed operator associativity: most operations are left-associative, exponentiation (^) is right-associative.

v3.3.01^[22] (2024-08-09)

• substr() no longer fails on out-of-range arguments.
• Output redirection (>) is supported within print statements.
• Fixed the argument order in extension function calls.

v3.3.00^[23] (2024-02-04)

• Fixed the evaluation order in string concatenation and in function argument lists.

v3.2.00^[24] (2024-02-01)

• exit NN returns the proper exit code from BEGIN and main rules.
• Full support for the ORS special variable.
• Full support for range patterns (/start/, /end/).
• NR is updated even when the program has no main rule.

v3.1.02^[25] (2024-01-18)

• !x on an uninitialized variable now correctly evaluates to true.

v3.1.01^[26] (2024-01-17)

• Fixed escaping in regexp constants, notably octal sequences.
• Improved syntax error messages.

v3.1.00^[27] (2024-01-17)

• Newlines are allowed after &&, ||, ?, :, and ,.
• Unary plus (+a) is supported.
• Fixed precedence of ternary and concatenation expressions; parsing and lexing follow gawk precedence rules for all operators.
• Fixed parsing of escape sequences in regular expression constants.
• Jawk runs on Java 8 and later.

v3.0.00^[28] (2023-12-14)

• printf() and sprintf() use the Printf4J^[29] library for C-style formatting.
• Java embedders: packages renamed from org.jawk to org.sentrysoftware.jawk; the library is licensed under LGPL and released on Maven Central.

v2.1.00 (beta)^[30] (2023)

• Octal ("\033") and hexadecimal ("\x1B") escape sequences are supported in strings.

See Also

• Compatibility and Compliance^[7]
• GitHub releases^[1]