If debugger is not available say so This build on sparc64 was configured with no debugger:

[XVilka]

r2 -d /bin/ls

Cannot use 'sparc' anal plugin.
asm.arch: cannot find (sparc)
Cannot use 'sparc' anal plugin.
r_syscall_setup: Unknown os/arch 'openbsd'/'sparc'
asm.arch: Cannot setup syscall os/arch for 'sparc'
e asm.bits: Cannot set value, no plugins defined yet
r_syscall_setup: Unknown os/arch 'openbsd'/'sparc'
asm.os: Cannot setup syscall os/arch for 'openbsd'
e asm.bits: Cannot set value, no plugins defined yet
asm.arch: cannot find (sparc)
Cannot use 'sparc' anal plugin.
r_syscall_setup: Unknown os/arch 'openbsd'/'sparc'
asm.arch: Cannot setup syscall os/arch for 'sparc'
Cannot open file.

Can't we just say "this version of radare2 was not built with the debugger". And exit.

P.S. Moved from http://rada.re/y/bugs.php?bugs&s=view&id=40

[radare]

Fixed in git. Thanks for the suggestion. The rest of errors come from an old version.

Passing -d when r2 is compiled without debugger will just show an error message.