Radare2- How to see stdout in Visual Mode

Question

How can I display any standard write in visual mode.

For example if I run dc command it runs the program normally and displays all the text normally. But if I enter visual mode with V< enter > and use S to run through the program it displays the output maybe a 1/10th of a second:

Can I have it display it for longer, or enter a command and see what has been printed to stdout so far?

Answer 1

I'm afraid there's no straight way to do so. You'll need to use rarun2 or radare's dd command.

I prefer the rarun2 way, it is more flexible and simple.

From man rarun2 output:

  Debugging a program redirecting io to another terminal

   ## open a new terminal and type 'tty' to get
   $ tty ; clear ; sleep 999999
   /dev/ttyS010

   ## in another terminal run r2
   $ r2 -e dbg.profile=foo.rr2 -d ls

   ## or you can use -R option
   $ r2 -R foo.rr2 -d ls
   $ cat foo.rr2
   #!/usr/bin/rarun2
   stdio=/dev/ttys010

For a step-by-step guide and more detailed answer, check my answer to a similar question here.

dd can be used to change file descriptors at runtime:

[0x00000000]> dd?
|Usage: dd Descriptors commands
| dd                   List file descriptors
| dd <file>            Open and map that file into the UI
| dd-<fd>              Close stdout fd
| dd*                  List file descriptors (in radare commands)
| dds <fd> <off>       Seek given fd)
| ddd <fd1> <fd2>      Dup2 from fd1 to fd2
| ddr <fd> <size>      Read N bytes from fd
| ddw <fd> <hexpairs>  Write N bytes to fd