VIM Trick: Forgot to sudo before editing the file?

" Allow saving of files as sudo when I forgot to start vim using sudo.
cmap w!! w !sudo tee > /dev/null %

Reference: http://stackoverflow.com/questions/2600783/how-does-the-vim-write-with-sudo-trick-work

Ubuntu: Completely restart wireless network

driver=`sudo ethtool -i wlan0 | grep driver | cut -d ' ' -f 2`;sudo modprobe -r $driver;sudo modprobe $driver;

How to restart scim without restarting gdm

pkill ^scim && scim -d && scim-bridge

dlopen(0, RTLD_NOW | RTLD_GLOBAL) doesn't work?

You need to compile the binary with -rdynamic flag to expose all the symbols in the  binary, otherwise, it is highly possible that the symbol could not be found.

Linux: generate random number using command line

od -An -N2 /dev/random
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Copy backtrace log to file

According to this link:

gdb -batch-silent -ex "run" -ex "set logging overwrite on" -ex "set logging file gdb.bt" -ex "set logging on" -ex "set pagination off" -ex "handle SIG33 pass nostop noprint" -ex "echo backtrace:\n" -ex "backtrace full" -ex "echo \n\nregisters:\n" -ex "info registers" -ex "echo \n\ncurrent instructions:\n" -ex "x/16i \$pc" -ex "echo \n\nthreads backtrace:\n" -ex "thread apply all backtrace" -ex "set logging off" -ex "quit" --args'

you can use those arguments to dump your huge bt log into a file!

Get all network interfaces using SIOCGIFCONF

Use ioctl with SIOCGIFCONF can get the names of every network interface in your machine. It should be faster than parsing the output of "ifconfig" command.