awk help needed

[Chris F.A. Johnson]

On Sun, 19 Jul 2009, Jamon Camisso wrote:

> Giles Orr wrote:
>> 2009/7/18 Alex Beamish <talexb-Re5JQEeQqe8AvxtiuMwx3w at public.gmane.org>:
>>> On Sat, Jul 18, 2009 at 11:46 AM, Giles Orr<gilesorr-Re5JQEeQqe8AvxtiuMwx3w at public.gmane.org> wrote:
>>>> 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.
>>> Sorry, but I usually use the du command for this.
>>>
>>>  root at music:/etc/init.d# du -h .
>>>  504K    .
>>> 
>>> Sometimes I want to know how heavy an entire tree is, so I use
>>>
>>>  $ du -sh foo
>>> 
>>> The 'h' argument does intelligent size management, so shows K, M and G.
>> 
>> I would love to use "du" because initially it seems like precisely the
>> right tool ... but I want only the sum of the sizes of the files in
>> the current directory, and "du" is by default recursive (which also
>> makes it painfully slow to return, not a good thing for something
>> incorporated into a Bash prompt).  If it's possible to stop "du" from
>> recursing, I'll use it immediately - but that looks difficult to
>> impossible.  Any thoughts?
>> 
>> Thanks to everyone else who answered too: it all helped.  It certainly
>> sounds like piping into "awk" is the way to go rather than trying to
>> write a self-contained "awk" script.
>> 
>
> Try this:

   DON'T.

> #!/bin/bash
>
> i=0 j=0 k=0
> echo -n "Enter directory: "
> read dir
> for i in `ls $dir`

     Not only is ls unnecessary, but it will cause the script to fail
     if any filenames contain spaces or other pathological characters.
     Use:

for i in "$dir"/*

>  do
>    if [ -f $i ]; then
>      j=`du -s $i |awk '{print $1}'`
>      k=`expr $k + $j`
>    fi
>  done
> echo $k


-- 
    Chris F.A. Johnson                      <http://cfaj.freeshell.org>
    ===================================================================
    Author:
    Shell Scripting Recipes: A Problem-Solution Approach (2005, Apress)
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