Date: Thu, 14 Aug 2003 18:34:25 +0100 From: Jez Hancock <jez.hancock@munk.nu> To: freebsd-questions@freebsd.org Subject: Re: Using bc in bash script Message-ID: <20030814173425.GA78559@users.munk.nu> In-Reply-To: <20030814122334.0a05ab4b.nospam@hiltonbsd.com> References: <20030814115313.2707cb21.nospam@hiltonbsd.com> <003001c36287$2a2a7b40$04fea8c0@moe> <20030814122334.0a05ab4b.nospam@hiltonbsd.com>
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On Thu, Aug 14, 2003 at 12:23:34PM -0500, Stephen Hilton wrote:
> On Thu, 14 Aug 2003 12:11:55 -0500
> "Charles Howse" <chowse@charter.net> wrote:
>
> > > Charles,
> > >
> > > This will set bc precision to 5 decimal places:
> > >
> > > et=`echo "scale=5 ; $end_time - $start_time" | bc`
> >
> > Ohhh, I was really hoping on that one...but no, it still reports 0
> > seconds.
>
>
> Sorry I jumped the gun there, the scale is needed for this to work
> but the "date +%s" willonly resolve into whole seconds after reading
> the date man page.
>
> I sure am curious as to how to solve this also, the /usr/bin/time
> command man page says this:
>
> -----------------snip------------------
> DESCRIPTION
> The time utility executes and times the specified utility. After the
> utility finishes, time writes to the standard error stream, (in seconds):
> the total time elapsed, the time used to execute the utility process and
> the time consumed by system overhead.
> -----------------snip------------------
>
> So that looks like seconds only also.
The precision is in hundredths of a second as I understand it from
playing with time(!):
#!/bin/sh
time_file=tmp.time
time="time -a -o $time_file"
$time cat /var/log/messages >/dev/null 2>&1
$time cat /var/log/maillog >/dev/null 2>&1
awk '{sum+=$1}END{print sum}' $time_file
rm $time_file
which outputs:
[18:34:03] munk@users /home/munk# sh tmp.sh
0.01
This simple script just times each cat command and appends the output from
time to the $time_file, then prints out the sum of the first columns of
the time outputs found in the time file.
Just an idea.
--
Jez
http://www.munk.nu/
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