Shell Programming and Scripting

awk     'NF==1  {print | "sort"}        # one field: record member; add to sort input via pipe; sort will print to stdout when pipe is closed.
         NF!=1  {close ("sort"); print} # record header or empty line; close the sort pipe to finish sorting the record; print header to stdou
        ' file

S 0.0 0.0 (reg, inst050)
kfdasdf dsaf
easd sadfas 
ffadsfasfdsadsa  dsafdsafas
dd8385fdsa asdasdfaf2432vdsaf 
dsafcfasfdsa f32f32asf322dsdsaf

awk '
!NF || /^S .*[(].*[)]$/ {
	# Close pipe to sort when we get a blank line or a section header.
	close("sort")
	# Copy the blank or section header line to standard output.
	print
	next
}
{	# Feed other lines to sort.
	print | "sort"
}' file

awk 'BEGIN {
  # scan arrays by values ASCIIbetical order  
  PROCINFO["sorted_in"] = "@val_str_asc"
  }
{
  # split $0 by NL
  n = split($0, t, "\n")
  print t[1]; delete t[1]
  # output in order
  for (e in t)
    print t[e]
  # print the logical RS    
  print ""    
  }' RS= infile

perl -F'\n' -lan00e'
  print join "\n", shift @F, (sort @F), $/
   ' infile