awk Command Builder & Tester
Build and test awk one-liners in the browser. A pure-JavaScript awk interpreter (no WASM, no network) runs BEGIN/END blocks, pattern { action } rules, field separators (-F / FS), -v variables, $0/$1/$N, NR/NF, OFS, print/printf, if/while/for, length/tolower/toupper/substr/split, regex patterns, arithmetic, comparisons, and string concatenation. Visual builder (pick columns, add a condition, choose an aggregation → generates the program), per-option plain-English explanation, reverse program explainer, sample-data library, recipe presets, GNU vs POSIX toggle, copy-ready `awk -F',' '{print $1,$3}' file` command, history (max 20), shareable URL. 100% client-side.
About awk Command Builder & Tester
Build and test awk one-liners in the browser. A pure-JavaScript awk interpreter (no WASM, no network) runs BEGIN/END blocks, pattern { action } rules, field separators (-F / FS), -v variables, $0/$1/$N, NR/NF, OFS, print/printf, if/while/for, length/tolower/toupper/substr/split, regex patterns, arithmetic, comparisons, and string concatenation. Visual builder (pick columns, add a condition, choose an aggregation → generates the program), per-option plain-English explanation, reverse program explainer, sample-data library, recipe presets, GNU vs POSIX toggle, copy-ready `awk -F',' '{print $1,$3}' file` command, history (max 20), shareable URL. 100% client-side. Everything runs locally in your browser — your data never leaves your device.
How to use
- Enter your input in the tool above.
- Adjust any options to your preference.
- Use the Copy or Download buttons to save the result.
- Everything happens locally — your data never leaves your browser.
FAQ
Is this a real awk engine?
It's a small pure-JavaScript awk interpreter built from scratch — no WASM, no network. It supports BEGIN/END blocks, pattern { action } rules, $0/$1/$N field access, NR/NF special variables, the -F field-separator flag, -v variable assignment, FS/OFS, print and printf, if/else, while, for, length/tolower/toupper/substr/split, arithmetic (+ - * / %), comparisons (== != < > <= >=), logical operators (&& || !), string concatenation, and /regex/ patterns. For features outside this subset (e.g. gawk-only extensions, associative arrays, functions, BEGINFILE/ENDFILE) use awk.js.org or gawk directly.
How does the visual builder work?
Pick the columns to print (comma-separated, e.g. 1,3), optionally add a condition (e.g. $2 > 100 or /pattern/), optionally choose an aggregation (sum, avg, min, max, count), choose a field separator, and the builder generates a valid awk program AND a copy-ready command `awk -F',' '{print $1,$3}' file`. Each option has a plain-English explanation showing what -F, -v, BEGIN, END, NR, NF, and OFS do in your specific program.
What does the reverse explainer do?
Paste any awk program (from a Stack Overflow answer or shell history) and the explainer annotates each token: $1, $2 → first/second field; NR → current record number; NF → field count; BEGIN{}/END{} → setup/teardown blocks; -F',' → comma field separator; -v var=val → variable pre-assignment; /pattern/ → regex match; print → output. Each annotation is plain English so non-experts can read the program.
How does field separator handling work?
Use -F',' (or FS="," in BEGIN) for CSV, -F' ' for TSV, -F':' for /etc/passwd. Default whitespace FS treats runs of spaces/tabs as a single separator and trims leading/trailing — matching awk CLI behavior. Multi-character literal separators (e.g. -F'::') are supported; regex separators (e.g. -F'[,:]' to split on either comma or colon) are also supported by the interpreter.
What extra features does this tool have versus awk.js.org?
(1) Pure-JS interpreter — instant load, works offline, no WASM. (2) Visual builder that generates valid awk for print columns, filter by pattern, sum/avg/min/max/count. (3) Per-option explanation in plain English. (4) Reverse explainer that annotates a pasted program. (5) Recipe library (10 common one-liners). (6) Sample data library (CSV, TSV, /etc/passwd, access log). (7) GNU vs POSIX toggle changes the example invocation comment. (8) Auto shell-quoting of the program (single quotes, with proper escaping). (9) Copy command + copy output. (10) localStorage history (max 20). (11) Shareable URL with embedded program + input. 100% client-side — your text never leaves the device.
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