[Wien] x lstart -sigma: key Print/No doesn't work

[Lyudmila Dobysheva]

Dear all,

I am understanding something wrong with making a difference plot of 
electron density. Manual says that some orbitals can be chosen using key 
P or N (print or no) in case.inst, than program lstart copies it to 
case.inst_sigma, and makes the file case.sigma that later will be 
subtracted from the scf electron density by lapw5.
But I see that x lstart replaces all N with P, and the file case.sigma 
is always the same.
Here are the lines from x_lapw:
-------------------------
if ($?sigma) then
#  if(  -z $file.inst_sigma ) then
     sed "s/ N/ P/" $file.inst >$file.inst_sigma
#  endif
-------------------------

man sed tells:
-------------------------
s/regexp/replacement/     Attempt  to  match  regexp  against the 
pattern space.  If successful, replace that portion matched with 
replacement.
-------------------------

Why is here this replacing and simple copy?

Best wishes to all and good health.
Lyudmila Dobysheva
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http://ftiudm.ru/content/view/25/103/lang,english/
Physics-Techn.Institute,
Udmurt Federal Research Center, Ural Br. of Rus.Ac.Sci.
426000 Izhevsk Kirov str. 132
Russia
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