To find a folder with size more than 1 gb
 du -ck ~ | awk '{if ($1>1048576) print $0 }'

To find folder size
du -sh <foldername>

To copy recent files from a folder to somewhere else:
cp $(ls -lrt | tail -2 |awk '{print $9}') ../ (copying last 2 recent files smwer)

To find a word in a directory lets say err

ls -Rl | grep ^-r | awk '{print $10}' |xargs cat | grep -w import
or
ls -Rl | grep ^-r | awk '{print $10}' |xargs cat | grep '\bimport\b'

Suppose you are on top windo and want to kill a process. what to do ???

hit 'Q' and then do usual kill stuff . well but there is a choice. dnt quit and hit 'k'.

it will ask for id.give the id and it will kill the process. :)

if a grep statement is successful then it retun 0 if failed then it returns 1.

bingo !

creating alias in mac/linux/unix/cent OS :)

alias ll="ls -lrt"

Caution : This will not remail permanent. add this line to ~/.bash_profile .Quit terminal and boom !!!

it's working now.