Radare2 Reference Card

This chapter is based on the Radare 2 reference card by Thanat0s, which is under the GNU GPL. Original license is as follows:

This card may be freely distributed under the terms of the GNU
general public licence — Copyright by Thanat0s - v0.1 -

Survival Guide

Those are the basic commands you will want to know and use for moving around a binary and getting information about it.

CommandDescription
s (tab)Seek to a different place
x [nbytes]Hexdump of nbytes, $b by default
aaAuto analyze
pdf@fcn(Tab)Disassemble function
f fcn(Tab)List functions
f str(Tab)List strings
fr [flagname] [newname]Rename flag
psz [offset]~grepPrint strings and grep for one
arf [flag]Find cross reference for a flag

Flags

Flags are like bookmarks, but they carry some extra information like size, tags or associated flagspace. Use the f command to list, set, get them.

CommandDescription
fList flags
fd $$Describe an offset
fjDisplay flags in JSON
flShow flag length
fxShow hexdump of flag
fC [name] [comment]Set flag comment

Flagspaces

Flags are created into a flagspace, by default none is selected, and listing flags will list them all. To display a subset of flags you can use the fs command to restrict it.

CommandDescription
fsDisplay flagspaces
fs *Select all flagspaces
fs [sections]Select one flagspace

Information

Binary files have information stored inside the headers. The i command uses the RBin api and allows us to the same things rabin2 do. Those are the most common ones.

CommandDescription
iiInformation on imports
iIInfo on binary
ieDisplay entrypoint
iSDisplay sections
irDisplay relocations
izList strings (izz, izzz)

Print string

There are different ways to represent a string in memory. The ps command allows us to print it in utf-16, pascal, zero terminated, .. formats.

CommandDescription
psz [offset]Print zero terminated string
psb [offset]Print strings in current block
psx [offset]Show string with scaped chars
psp [offset]Print pascal string
psw [offset]Print wide string

Visual mode

The visual mode is the standard interactive interface of radare2.

To enter in visual mode use the v or V command, and then you'll only have to press keys to get the actions happen instead of commands.

CommandDescription
VEnter visual mode
p/PRotate modes (hex, disasm, debug, words, buf)
cToggle (c)ursor
qBack to Radare shell
hjklMove around (or HJKL) (left-down-up-right)
EnterFollow address of jump/call
sSStep/step over
oGo/seek to given offset
.Seek to program counter
/In cursor mode, search in current block
:cmdRun radare command
;[-]cmtAdd/remove comment
x+-/[]Change block size, [] = resize hex.cols
>||<Seek aligned to block size
i/a/A(i)nsert hex, (a)ssemble code, visual (A)ssembler
b/BToggle breakpoint / automatic block size
d[f?]Define function, data, code, ..
DEnter visual diff mode (set diff.from/to)
eEdit eval configuration variables
f/FSet/unset flag
gGGo seek to begin and end of file (0-$s)
mK/’KMark/go to Key (any key)
MWalk the mounted filesystems
n/NSeek next/prev function/flag/hit (scr.nkey)
oGo/seek to given offset
CToggle (C)olors
RRandomize color palette (ecr)
tTrack flags (browse symbols, functions..)
TBrowse anal info and comments
vVisual code analysis menu
V/W(V)iew graph (agv?), open (W)ebUI
uUUndo/redo seek
xShow xrefs to seek between them
yYCopy and paste selection
zToggle zoom mode

Searching

There are many situations where we need to find a value inside a binary or in some specific regions. Use the e search.in=? command to choose where the / command may search for the given value.

CommandDescription
/ foo\00Search for string ’foo\0’
/bSearch backwards
//Repeat last search
/w fooSearch for wide string ’f\0o\0o\0’
/wi fooSearch for wide string ignoring case
/! ffSearch for first occurrence not matching
/i fooSearch for string ’foo’ ignoring case
/e /E.F/iMatch regular expression
/x a1b2c3Search for bytes; spaces and uppercase nibbles are allowed, same as /x A1 B2 C3
/x a1..c3Search for bytes ignoring some nibbles (auto-generates mask, in this example: ff00ff)
/x a1b2:fff3Search for bytes with mask (specify individual bits)
/d 101112Search for a deltified sequence of bytes
/!x 00Inverse hexa search (find first byte != 0x00)
/c jmp [esp]Search for asm code (see search.asmstr)
/a jmp eaxAssemble opcode and search its bytes
/ASearch for AES expanded keys
/r sym.printfAnalyze opcode reference an offset
/RSearch for ROP gadgets
/PShow offset of previous instruction
/m magicfileSearch for matching magic file
/p patternsizeSearch for pattern of given size
/z min maxSearch for strings of given size
/v[?248] numLook for a asm.bigendian 32bit value

Saving

By default, when you open a file in write mode (r2 -w) all changes will be written directly into the file. No undo history is saved by default.

Use e io.cache.write=true and the wc command to manage the write cache history changes. To undo, redo, commit them to write the changes on the file..

If, instead, we want to save the analysis information, comments, flags and other user-created metadata, we may want to use projects with r2 -p and the P command.

CommandDescription
Po [file]Open project
Ps [file]Save project
Pi [file]Show project information

Usable variables in expression

The ?$? command will display the variables that can be used in any math operation inside the r2 shell. For example, using the ? $$ command to evaluate a number or ?v to just the value in one format.

All commands in r2 that accept a number supports the use of those variables.

CommandDescription
$$here (current virtual seek)
$$$current non-temporary virtual seek
$?last comparison value
$alias=valuealias commands (simple macros)
$bblock size
$Bbase address (aligned lowest map address)
$fjump fail address (e.g. jz 0x10 => next instruction)
$flflag length (size) at current address (fla; pD $l @ entry0)
$Fcurrent function size
$FBbegin of function
$Fbaddress of the current basic block
$Fssize of the current basic block
$FEend of function
$FSfunction size
$Fjfunction jump destination
$Fffunction false destination
$FIfunction instructions
$c,$rget width and height of terminal
$Cnget nth call of function
$Dnget nth data reference in function
$Dcurrent debug map base address ?v $D @ rsp
$DDcurrent debug map size
$e1 if end of block, else 0
$jjump address (e.g. jmp 0x10, jz 0x10 => 0x10)
$Jaget nth jump of function
$Xnget nth xref of function
$lopcode length
$mopcode memory reference (e.g. mov eax,[0x10] => 0x10)
$Mmap address (lowest map address)
$ohere (current disk io offset)
$pgetpid()
$Ppid of children (only in debug)
$sfile size
$Ssection offset
$SSsection size
$vopcode immediate value (e.g. lui a0,0x8010 => 0x8010)
$wget word size, 4 if asm.bits=32, 8 if 64, ...
${ev}get value of eval config variable
$r{reg}get value of named register
$k{kv}get value of an sdb query value
$s{flag}get size of flag
RNum$variables usable in math expressions