line number

nl: number lines

cpu info

cat /proc/cpuinfo

interrupt context

1. can not relinquish cpu by calling sleep functions

GFP_KERNEL

allocate memory:

1. GFP_KERNEL:

    kmalloc() is allowed to go to sleep and wait for pages to get freed up.

2.GFP_ATOMIC:

   Used by interrupt context code to get hold of memory. In this mode, kmalloc() is not allowed to    sleep-wait for free pages, so the probability of successful allocation with GFP_ATOMIC is lower    than with GFP_KERNEL.

df

show disk space

ex: df  -h:

Filesystem            Size  Used Avail Use% Mounted on

/dev/hda3             9.9G  7.0G  2.4G  75% /

udev                  8.0G  132K  8.0G   1% /dev

objdump

show assembly of program:
ex:

objdump -D test.o

fsck

check file system