If you happened to meet with a sentence like 'I accidentally the kernel with radare2.' or 'Everytime you run radare2, a random file is removed :)', don't be scared don't be serious, is just a joke (hopefully). There is a file, 'fortunes.fun', under radare2/doc. Every time r2 is run, a random line of them will output to the screen. So just relax and enjoy the excellent experience of REing with r2.
0x01 Useful Instructions
You can type
<instruction>? to get help info, like
Here comes some most often used instructions when re a bin file.
aaa- analyse the program, only after you analyse some parts of the program (like functions), can you output the result of them (say, afl to output function list)
afl- 'analyse function llist', this will list useful functions in the program as well as their flag names and offset addresses. Like this:
s sym.main- set current address to the start of sym.main(), then you can
pD firstname.lastname@example.org- disassemble and print the first 60 bytes start from the sym.shellcode's address.
email@example.com- directly disassemble and print the first n bytes start from the sym.main's address, n means your current block size.
b- display current block size.
0x02 Normal Usage and Order
Normally, when you got a binary going to be REed,
first take a glance at its file info and try to run it (if cannot run, try chmod).
Then open it with r2.
i to gether some overall info.
aaa to analyse it.
afl to look at how many functions are there in the program.
Then you can
s sym.main, or just
s main for short, to jump to the main funciton,
If you find something interested, just use
s to jump to it and
pd or pD to print the disassembling result.