How to Automate Tasks with HexTool ScriptsAutomation saves time, reduces errors, and lets you focus on higher‑value work. HexTool — a powerful hex editor and binary-manipulation utility — includes a scripting system that can automate repetitive editing, batch process files, and integrate with build or QA pipelines. This article explains how to design, write, test, and deploy HexTool scripts, with practical examples and troubleshooting tips.
What you can automate with HexTool scripts
HexTool scripts let you:
- Batch edit bytes across many files (patch headers, change magic numbers).
- Search and replace complex byte patterns, including wildcards and mask-based matches.
- Apply checksums and cryptographic hashes after modifications.
- Extract or inject binary chunks (resources, metadata).
- Convert or normalize file formats when the transformation is byte-level.
- Integrate into CI/CD pipelines for automatic validation or binary stamping.
HexTool scripting basics
HexTool’s scripting language (examples here use a typical procedural syntax — check your HexTool version for exact keywords) provides:
- File I/O primitives: open, read, write, seek, close.
- Pattern search with masks and wildcards.
- Byte-level read/write operations and typed reads/writes (integers of various endianness).
- Control flow: conditionals, loops, functions/macros.
- Error handling and logging.
- Command-line parameter support so scripts can be reused in batch workflows.
Example script structure:
- Parse command-line arguments (input file(s), mode, offsets).
- Open target file(s) in read/write or read-only mode.
- Locate target patterns or offsets.
- Make changes or extract data.
- Recompute checksums if needed.
- Save and close file(s).
- Log results and exit with status codes.
Common scripting patterns
- Parameterized patching
- Accept an input filename and a patch specification (offset and bytes or a pattern -> replacement).
- Validate file size and offset ranges before writing.
- Back up original file or write to a new output file.
- Pattern-driven replacement
- Use masked searches to find sequences that vary in certain bits.
- Replace matched regions with computed values or templates.
- Chunk extraction and injection
- Locate chunk headers (e.g., four-byte identifiers and length fields).
- Extract chunk data to separate files or inject new data, updating length fields.
- Checksum and hash recalculation
- After edits, recompute CRC32, MD5, SHA1, or custom checksums and write them to the expected offset(s).
- Multi-file batch processing
- Iterate over a directory or list of files, applying the same modification with error aggregation and parallelism if supported.
Example scripts
Below are illustrative examples. Adapt syntax to your HexTool version.
- Patch a 4-byte little-endian integer at a given offset (command-line: inputfile offset newvalue)
// PatchInt.hts (illustrative) func parseArgs() { if (argc < 4) { print("Usage: PatchInt.hts <file> <offset> <newValue>"); exit(1); } return { file: argv[1], offset: toNumber(argv[2]), value: toNumber(argv[3]) }; } main() { args = parseArgs(); f = open(args.file, "r+"); if (!f) { print("Cannot open file"); exit(2); } size = f.size(); if (args.offset < 0 || args.offset + 4 > size) { print("Offset out of range"); close(f); exit(3); } f.seek(args.offset); old = f.readUInt32LE(); print("Old value:", old); f.seek(args.offset); f.writeUInt32LE(args.value); print("Wrote new value:", args.value); close(f); } - Search and replace a byte pattern with mask support
// ReplacePattern.hts (illustrative) pattern = hexToBytes("DE AD BE EF"); mask = hexToBytes("FF FF 00 FF"); // third byte is ignored in match replacement = hexToBytes("CA FE 00 BA"); files = listFiles(argv[1]); // or take single filename for (fpath in files) { f = open(fpath, "r+"); positions = f.findAll(pattern, mask); for (pos in positions) { f.seek(pos); f.write(replacement); print("Patched", fpath, "at", pos); } close(f); } - Recompute CRC32 for a region and write result at footer
// RecalcCRC.hts f = open(argv[1], "r+"); data = f.readRange(0, f.size() - 4); // all but last 4 bytes crc = crc32(data); f.seek(f.size() - 4); f.writeUInt32LE(crc); print("Wrote CRC32:", toHex(crc)); close(f); Integrating with other tools and CI
- Call HexTool scripts from shell scripts, Makefiles, or CI steps (GitHub Actions, GitLab CI, Jenkins).
- Use exit codes to mark failures; print machine-readable logs (JSON) for parsers.
- Keep backups or use immutable artifact pipelines: write modified files to new artifact paths rather than overwriting originals.
- For large batches, parallelize with caution — ensure scripts don’t collide on shared files.
Example GitHub Actions step (conceptual):
- Run HexTool to stamp build ID into binaries as part of release workflow.
- Verify checksums, fail the build if mismatch.
Testing and safety
- Always test scripts on copies and test fixtures that cover edge cases: minimal-size files, truncated headers, invalid checksums.
- Add assertions for file sizes, expected magic numbers, or structure versions.
- Implement an undo feature or create automatic backups (e.g., filename.bak with timestamp).
- Use verbose and dry-run modes so you can preview changes before applying them.
Performance considerations
- For large files, prefer streaming reads/writes and operate on byte ranges rather than loading entire files into memory.
- Use efficient search algorithms (Boyer–Moore variant) if your HexTool supports it.
- If modifying many small files, reduce process startup overhead by batching filenames to one script invocation.
Troubleshooting common issues
- Script won’t open file: check permissions and whether another process locks the file.
- Pattern not found: confirm endianness, masking, and ensure your pattern accounts for variable fields.
- CRC or signature verification fails: verify you’re computing the same variant (endianness, polynomial, initial/final XORs).
- Partial writes or corrupted output: ensure you open files in binary mode and properly handle errors.
Example workflows (practical uses)
- Firmware release pipeline
- Insert build number and date into firmware image.
- Recompute and write signature/checksum.
- Run smoke tests that validate header values.
- Game modding toolkit
- Batch-patch asset files to change resource pointers.
- Extract textures/resources for editing, then repackage with correct chunk sizes.
- Malware analysis / reverse engineering (defensive, ethical)
- Automate extraction of embedded resources or known markers across many samples for triage.
Final tips
- Keep scripts modular: small functions are easier to test and reuse.
- Document expected file formats and offsets alongside scripts.
- Use version control for scripts and include sample files and test vectors.
- Prefer non-destructive defaults (dry-run, backups).
If you want, tell me your HexTool version and a specific task (e.g., “insert timestamp at offset 0x200 and recalc CRC32”) and I’ll draft a ready-to-run script tailored to that.