Wednesday, May 6, 2009

removing duplicate files using shell script

Friends,

One liner script provided below, can be used to identify the duplicate files within the system. If you want to search in a partticular path, just replace it with "/tmp" provided in sample command. It will redirect all the duplicate file names into removal_list.txt which can be used to delete them.

find /tmp "$@" -type f -print0 xargs -0 -n1 md5sum sort --key=1,32 uniq -w 32 -d --all-repeated=separate sed -r 's/^[0-9a-f]*( )*//;s/([^a-zA-Z0-9./_-])/\\\1/g;s/(.+)/#rm \1/' >> removal_list.txt

Performance comparision

Checkout the "time" command.

For checking the time taken for execution of any command do the following:

Say you want to execute "ls -l grep sanju.txt" and measure time taken for this.
Now open a bash shell and on the prompt
$time ls -l grep sanju.txt

it shows you the time taken by the command execution

Tuesday, May 5, 2009

Unaliasing in BASH

Unaliasing in BASH
How can we unalias a command temporarily without using unalias command ?

just put the escape character before the command i.e. "\"e.g. :-

$\ls

It will show the without alias.

Thursday, January 22, 2009

How to count a particular word in VI?

If you want to count a particular word, say PROG, in a file, try this trick

:1,$s/zebra/&/g

or

if you want to count all words in a file, try

g [ctrl-g] at command mode

source: http://www.vim.org/tips/tip.php?tip_id=689

Some useful commands

df : report disk free space
gview : load VIM, improved vi editor
history : display a list of previous commands
!! : repeat previous command
ls -p grep "/" : list sub-directories in the current directory
touch file.ext : create a NULL file named 'file.ext'
vmstat : virtual memory status
uname : system information

How to kill a hanged/freezed application ?

Have you ever faced a hanged/freezed application while working at GUI of linux/sun etc?
If yes, this topic is for YOU.

Xkill is a utility for forcing the X server to close connections to clients. This program is very dangerous, but is useful for aborting programs that have displayed undesired windows on a user's screen. If no resource identifier is given with -id, xkill will display a special cursor as a prompt for the user to select a window to be killed.

We can use 'xkill' for a hard-to-kill frozen application. First, open a new terminal and type "xkill". After this your cursor will be a square-shaped.

Move to frozen findow and click.