sudo ls -l /dev/sda*# list all disc partitions
sudo ls -l /dev/sdb*#list all usb devices and parts
sudo fdisk -l ~# details about partitions and discs of all kind
sudo grep -rl BOOT_IMAGE# list all files who have this name
grep "^c" # grep lines starting with a c (character device)
## start : create a device on linux
med@raspberrypi:/tmp $ sudo mknod shity_device c 1 2
med@raspberrypi:/tmp $ cat shity_device
cat: shity_device: No such device or address
## done
file /usr/sbin/init ## what s this file 
ls -l /lib/modules/$(uname -r) #add output of command to argument
grep -rf ftracec. | grep -v output #search on doc kernel about ftrace
grep -rli sys_read include #search for files inclufing sys_read , ignoring case and search on all subdic on include