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fsuite

🔬 fprobe

Binary / bundle inspection + patching

Section titled “Binary / bundle inspection + patching”

fprobe is part of the fsuite toolkit — a set of fourteen CLI tools built for AI coding agents.

fprobe Binary / bundle inspection + patching · text tools can't reach
RoleBINARY
Chain positionspecialist branch
Use whentarget is compiled or obfuscated
Subcommandsstrings · scan · window · patch

fprobe is for the targets text tools can’t read — compiled binaries, minified bundles, obfuscated libraries. Four subcommands cover the workflow:

  • strings — extract printable strings (with length and substring filters)
  • scan — find a literal byte pattern, return offsets + context
  • window — read N bytes before/after an offset, decoded as text or hex
  • patch — write bytes at an offset with safety guards

This is the binary recon branch — when fcontent returns nothing because the file isn’t text, fprobe is the next move.

Canonical chains

Section titled “Canonical chains”
Terminal window
# Extract printable strings, filtered
fprobe strings /usr/local/bin/myapp --min-len 8 --filter "http"


# Locate a literal pattern
fprobe scan /usr/local/bin/myapp --pattern "userFacingName" -o json


# Read context around an offset
fprobe window /usr/local/bin/myapp --offset 0x100 --before 64 --after 256


# Hex dump
fprobe window /usr/local/bin/myapp --offset 0x100 --after 256 --decode hex


# Full binary recon chain
fprobe scan binary --pattern "renderTool" --context 300 -o json
fprobe strings binary --filter "diffAdded"
fprobe window binary --offset 112730723 --before 50 --after 200

Help output

Section titled “Help output”

The content below is the live --help output of fprobe, captured at build time from the tool binary itself. It cannot drift from the source — regenerating the docs regenerates this section.

fprobe — binary/opaque file reconnaissance


USAGE
  fprobe strings <file> [--filter <literal>] [--ignore-case] [-o pretty|json]
  fprobe scan    <file> --pattern <literal> [--context N] [--ignore-case] [-o pretty|json]
  fprobe window  <file> --offset N [--before N] [--after N] [--decode printable|utf8|hex] [-o pretty|json]
  fprobe patch   <file> --target <text> --replacement <text> [--dry-run]


  fprobe --version
  fprobe --help


DESCRIPTION
  Binary reconnaissance and surgical patching for opaque files — compiled
  binaries, SEA bundles, packed assets.


  strings   Extract printable ASCII runs (≥6 chars). --filter narrows to matches.
  scan      Find literal byte patterns. Returns offset + surrounding context.
  window    Read raw bytes at a known offset. Decode as printable, utf8, or hex.
  patch     Find and replace a literal byte pattern. Same-length enforced (pads
            with spaces if replacement is shorter). Creates .bak backup on first
            write. Uses rename for atomic swap (handles "Text file busy").


OUTPUT MODES
  -o pretty   Human-readable (default for terminal)
  -o json     Machine-readable JSON (default when piped)


EXAMPLES
  fprobe strings claude-binary --filter "renderTool"
  fprobe scan claude-binary --pattern "userFacingName" --context 500
  fprobe window claude-binary --offset 112202147 --before 200 --after 3000
  fprobe window claude-binary --offset 0 --after 16 --decode hex
  fprobe patch claude-binary --target 'if(P&&!P.success)return null' --replacement 'if(0&&!P.success)return null'
  fprobe patch claude-binary --target 'old text' --replacement 'new text' --dry-run

See also

Section titled “See also”