awk help needed

[Giles Orr]

By way of introduction: I'm finally, finally trying to get a new
edition of the Bashprompt HOWTO out there.  This will probably result
in me posting a lot of detailed and mildly weird questions to this
list.  This is the first.

The intention of this script is to figure out how much space the files
in the current directory take up.  There are about a million ways to
do this - and yes, I know that "ls -l" spits out a "total" line: I
don't know what it's totaling, but my math has never agreed with it
... feel free to explain though.  I decided that I'd like to do this
as much in awk as possible since it does decimal math (unlike bash)
and it's certainly the easiest way to do the text parsing.  I've tried
bc as well, but you have to use other utility programs to parse and
split the input for it.

#! /usr/bin/awk -f

BEGIN {
  total = 0
  while ( ( "ls -l" | getline ) > 0 )
    total+=$5
  magnitude = 0
  while ( ( total/=1024 ) > 1 )
    magnitude++
  if ( magnitude == 0 ) scalesize = "B"
  if ( magnitude == 1 ) scalesize = "KiB"
  if ( magnitude == 2 ) scalesize = "MiB"
  if ( magnitude == 3 ) scalesize = "GiB"
  if ( magnitude == 4 ) scalesize = "TiB"
  if ( magnitude == 5 ) scalesize = "PiB"
  if ( magnitude == 6 ) scalesize = "EiB"
  if ( magnitude == 7 ) scalesize = "ZiB"
  if ( magnitude == 8 ) scalesize = "YiB"
  printf ("%.2f%s\n", (total*1024), scalesize)
}

The problem here is that I want to have the "total+=$5" line starting
with "/^-/" so it matches only files in the ls output.  But it barfs
if I try that.  I'm not quite sure what the problem is: perhaps
because we're in the BEGIN section, but I couldn't figure out how to
move the whole process into the body without it barfing again ... how
can I make the getline output the input to the body?  So as it stands,
this goes wrong anywhere there are character devices, for example
/dev/ , because field 5 isn't the file size.

I know I can do this sort of thing:

  ls -l | awk '/^-/ {total+=$5} ; END {printf ("%.0f", total) }'

But I'd like to have a fully self-contained awk script.  Any suggestions?

-- 
Giles
http://www.gilesorr.com/
gilesorr-Re5JQEeQqe8AvxtiuMwx3w at public.gmane.org
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