I can run `grep -r . /sys/class/power_supply/*hid*` in Ubuntu 13.04 without any problem.
But when I run it in Ubuntu 12.04, it shows some messages like "grep: warning: ...: recursive directory loop".
It seems to be another bug of grep in Ubuntu 12.04. :P
@pitti,
I can run `grep -r . /sys/class/ power_supply/ *hid*` in Ubuntu 13.04 without any problem.
But when I run it in Ubuntu 12.04, it shows some messages like "grep: warning: ...: recursive directory loop".
It seems to be another bug of grep in Ubuntu 12.04. :P