Output redirection in Android command line -

i'm trying execute following command:

arp -a 

and redirect output file. however,

arp -a > arg.log 

does not work. ideas?

edit: i'm using android 5.0 , command executed in /sdcard. output file arg.log created content 0.

so problem arp

arp -a > arp.log 

command takes couple of minutes complete , output flushed @ end.