Linux: how to remove ^M at each line end

I got an acsii file from a Window's user. If it is a regular windows text file, then I can use a command 'dos2unix' to convert it in unix format. However, it doesn't work. I use 'less' to have a look at it, it looks like:

line1^M line2^M

. If I use emacs to view it, it looks okay like a regular file. In order to convert it to unix format, I use 'gedit' to do the conversion. A user will be reminded that you save as which format...

linux: screen

screen is a useful command when you do not have other better choice like vnc, specially for background job running. One thing that bothered me is I cannot page up and down simply even specified by

screen -h 2000

So I have to enter copy/paste mode by: ctrl+a, esc, page down/up

linux: renice

from : http://linux.about.com/library/cmd/blcmdl8_renice.htm

Users other than the super-user may only alter the priority of processes they own, and can only monotonically increase their ``nice value'' within the range 0 to PRIO_MAX (20). (This prevents overriding administrative fiats.) The super-user may alter the priority of any process and set the priority to any value in the range PRIO_MIN (-20) to PRIO_MAX Useful priorities are: 20 (the affected processes will run only when nothing else in the system wants to), 0 (the ``base'' scheduling priority), anything negative (to make things go very fast).

linux: data transfter

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ROOT: make plots more beautiful

http://ultrahigh.org/2007/08/20/making-pretty-root-color-palettes/

In ROOT, we can change its default to make plots more beautiful.

void
set_plot_style()
{
const Int_t NRGBs = 5;
const Int_t NCont = 255;

Double_t stops[NRGBs] = { 0.00, 0.34, 0.61, 0.84, 1.00 };
Double_t red[NRGBs] = { 0.00, 0.00, 0.87, 1.00, 0.51 };
Double_t green[NRGBs] = { 0.00, 0.81, 1.00, 0.20, 0.00 };
Double_t blue[NRGBs] = { 0.51, 1.00, 0.12, 0.00, 0.00 };
TColor::CreateGradientColorTable(NRGBs, stops, red, green, blue, NCont);
gStyle->SetNumberContours(NCont);
}

Linux:bash:about "delete key"

When I use "delete key" in some bash terminal, the key sends a tilde "~" instead of deleting the char that is supposed to be deleted.

Find a solution:
1. In your $HOME directory, create or edit your keyboard-mapping file, $HOME/.inputrc
2. Add one mapping line:

"\M-[3~": delete-char

3. restart your terminal

Linux: how to reduce eps file size?

I have couples of eps files which have a large size (>10 MB). Thus when using them in Latex, the output files (either pdf or ps) become very large and very slow to view. So it is necessary to reduce them first. Here provided is an approch working in Linux.

1. Create a new open office drawing file, past your large eps file to the canvas.
   
2. Add your canvas hence it has no too much extra-space (magine)
   
3. Export your drawing file to a PDF file. Here you can use low compress factors etc.
   
4. Use "pdftops -eps YourFile.pdf" to get your small-size eps file

Note: You can use open office drawing to export your file to an eps file directly, however, the eps file is even larger than your original one, so this exporting is not useful.

Linux: overwrite

http://www.cyberciti.biz/tips/howto-keep-file-safe-from-overwriting.html

set -o noclobber
(no overwrite)

set +o noclobber
(overwrite)


Linux: VNC

I use the following line to start up:

vncserver :1 -name kde -geometry 1250x760 -depth 24