How r2cat Boosts Productivity — Real-World Examples

Advanced r2cat Tips and Tricks for Power Usersr2cat is a versatile tool that, when mastered, can significantly speed up reverse-engineering workflows, binary analysis, and malware research. This article gathers advanced, practical tips and tricks for power users who already know the basics of r2 (radare2) and r2cat. The aim is to help you automate repetitive tasks, craft efficient analysis pipelines, and extract deeper insights from binaries.

Prerequisites and assumptions

This guide assumes you are comfortable with:

Command-line usage and shell scripting.
Basic radare2 concepts: commands like aa, afl, pf, aflj, and key concepts such as functions, symbols, and basic block analysis.
r2cat installation and basic usage (connecting to a session, sending commands, receiving output).

1) Create a reusable r2cat command library

Save often-used r2cat command sequences as snippets. For example, create a “profile” to run a standard analysis when opening a binary:

# ~/r2cat_profiles/default.r2cat o entry0 aa aaa afl~main pdf @ main iz iS

Then load it quickly:

r2cat -s ~/r2cat_profiles/default.r2cat target_binary

Use profiles for different tasks: quick triage, deep analysis, or malware unpacking.

2) Use JSON outputs to build automated pipelines

Leverage radare2’s JSON outputs to parse and act programmatically. For example, extract functions and generate a report:

r2 -c "aaa; aflj" -q target_binary > functions.json jq '.[] | {name: .name, size: .size, offset: .offset}' functions.json > funcs_summary.json

From there, script automated checks (e.g., find unusually large functions, identify functions without references).

3) Combine r2cat with other tools via Unix pipes

Chain r2cat with grep, sed, awk, jq, and other CLI utilities to filter and transform results:

r2cat -c "aaa; aflj" target_binary | jq -r '.[].name' | grep -E 'auth|login|password'

This quickly surfaces candidate authentication functions.

4) Interactive sessions: use tmux or screen

Run r2cat inside tmux panes to maintain persistent analysis sessions. Example layout:

Left pane: interactive r2 (visual mode)
Right pane: logs, scripts, and live jq filtering of r2 outputs

Save and restore sessions for long investigations.

5) Use scripting APIs (Python, Node.js) to extend r2cat

Use r2pipe to integrate radare2/r2cat into Python or Node workflows. Example Python snippet to list strings and search for suspicious ones:

import r2pipe, json, re r = r2pipe.open('target_binary') r.cmd('aaa') strings = json.loads(r.cmd('izj')) suspicious = [s for s in strings if re.search(r'pass(word)?|secret|api', s, re.I)] print(suspicious) r.quit()

Wrap such scripts into automated triage tools.

6) Create custom commands and aliases

Define aliases in radare2’s r2rc or send them via r2cat to shorten complex command sequences:

# in ~/.radare2rc e cmd.cosmetic = true # alias to show function graph quickly # afgv = afl; agf @ main

Aliases speed up repeated workflows.

7) Visual graph tricks and exporting

Use radare2’s graph capabilities to visualize complex functions and export them to DOT for further editing:

r2 -c "aaa; agfd @ main > main.dot" target_binary dot -Tpng main.dot -o main.png

Then open main.png to study control flow, or import DOT into tools like Graphviz or Gephi for larger analyses.

8) Advanced searching with expressions and emulation

Use radare2’s search and ESIL emulation to trace behavior:

Use “/x” for hex patterns and “/r” for regex across file/ranges.
Use “aeim” and “aer” to emulate and inspect registers/memory.

Example: emulate a function to recover decrypted strings at runtime.

9) Handle packed or obfuscated binaries

r2cat can help orchestrate an unpacking workflow:

Identify entry stub and import table anomalies with “iI” and “i~”.
Use breakpoints and stepping (db, ds) in radare2’s debugger.
Dump memory regions after unpacking with “pm” or “px” and reanalyze.

Automate dumps via r2pipe when specific execution conditions are reached.

10) Collaborative workflows and notes

Store command histories and findings as r2cat scripts or markdown notes. Use version control (git) for profiles and analysis artifacts. Include metadata like sample hashes and environment used.

11) Performance tips

For very large binaries, prefer targeted analysis (aa with function discovery disabled globally) and analyze modules incrementally.
Use “e anal.depth” and related analysis config vars to limit recursive analysis where needed.

12) Example power-user workflow (end-to-end)

Run a triage profile: r2cat -s ~/profiles/triage.r2cat sample
Export functions JSON: r2 -c “aaa; aflj” -q sample > aflj.json
Filter for crypto/auth candidates using jq
Attach debugger to run until unpacked, dump memory regions
Re-open dumped region as new file and run deep analysis profile

13) Troubleshooting common issues

If JSON outputs are malformed, confirm radare2 version compatibility and use explicit flags like -c and -q.
When symbols are missing, try different loader options or provide external symbol maps.
For unstable r2 sessions, run commands in non-interactive mode via r2cat scripts.

14) Learning resources and staying current

Follow radare2/rizin communities, watch changelogs, and read plugin repositories. Build a small toolbox of scripts you can reuse and share with teammates.

Conclusion

Mastering r2cat is about building reliable, shareable automation, combining JSON outputs with scripting, and using radare2’s advanced analysis and debugging features. Treat r2cat as the glue that binds radare2 commands into repeatable, audited workflows.