I got it from the "info bash" command. I keep it around in a text file via the
command:
info bash >bash.info
<quote>
`${PARAMETER/PATTERN/STRING}'
The PATTERN is expanded to produce a pattern just as in filename
expansion. PARAMETER is expanded and the longest match of PATTERN
against its value is replaced with STRING. If PATTERN begins with
`/', all matches of PATTERN are replaced with STRING. Normally
only the first match is replaced. If PATTERN begins with `#', it
must match at the beginning of the expanded value of PARAMETER.
If PATTERN begins with `%', it must match at the end of the
expanded value of PARAMETER. If STRING is null, matches of
PATTERN are deleted and the `/' following PATTERN may be omitted.
If PARAMETER is `@' or `*', the substitution operation is applied
to each positional parameter in turn, and the expansion is the
resultant list. If PARAMETER is an array variable subscripted
with `@' or `*', the substitution operation is applied to each
member of the array in turn, and the expansion is the resultant
list.
</quote>
so the ${cpuutil/%.*/} replaces the first period and everything after it with
"" (nothing).
--
John McKown
Systems Engineer IV
IT
Administrative Services Group
HealthMarkets(r)
9151 Boulevard 26 * N. Richland Hills * TX 76010
(817) 255-3225 phone *
[email protected] * www.HealthMarkets.com
Confidentiality Notice: This e-mail message may contain confidential or
proprietary information. If you are not the intended recipient, please contact
the sender by reply e-mail and destroy all copies of the original message.
HealthMarkets(r) is the brand name for products underwritten and issued by the
insurance subsidiaries of HealthMarkets, Inc. -The Chesapeake Life Insurance
Company(r), Mid-West National Life Insurance Company of TennesseeSM and The
MEGA Life and Health Insurance Company.SM
> -----Original Message-----
> From: Linux on 390 Port [mailto:[email protected]] On
> Behalf Of Bauer, Bobby (NIH/CIT) [E]
> Sent: Wednesday, December 08, 2010 2:36 PM
> To: [email protected]
> Subject: Re: Need a little help with a Linux script
>
> Thanks John, worked perfectly. Can you explain a little what
> /%.*/ is doing or tell me what it is so I can do some reading.
>
> Bobby Bauer
> Center for Information Technology
> National Institutes of Health
> Bethesda, MD 20892-5628
> 301-594-7474
>
>
>
> -----Original Message-----
> From: McKown, John [mailto:[email protected]]
> Sent: Wednesday, December 08, 2010 2:59 PM
> To: [email protected]
> Subject: Re: Need a little help with a Linux script
>
> if [ ${cpuutil/%.*/} -ge 75 ]; then
>
> will drop the . and everthing after in ${cpuutil} if you're
> using BASH.
>
> --
> John McKown
> Systems Engineer IV
> IT
>
> Administrative Services Group
>
> HealthMarkets(r)
>
> 9151 Boulevard 26 * N. Richland Hills * TX 76010
> (817) 255-3225 phone *
> [email protected] * www.HealthMarkets.com
>
> Confidentiality Notice: This e-mail message may contain
> confidential or proprietary information. If you are not the
> intended recipient, please contact the sender by reply e-mail
> and destroy all copies of the original message.
> HealthMarkets(r) is the brand name for products underwritten
> and issued by the insurance subsidiaries of HealthMarkets,
> Inc. -The Chesapeake Life Insurance Company(r), Mid-West
> National Life Insurance Company of TennesseeSM and The MEGA
> Life and Health Insurance Company.SM
>
>
>
> > -----Original Message-----
> > From: Linux on 390 Port [mailto:[email protected]] On
> > Behalf Of Bauer, Bobby (NIH/CIT) [E]
> > Sent: Wednesday, December 08, 2010 1:41 PM
> > To: [email protected]
> > Subject: Need a little help with a Linux script
> >
> > I'm trying to write a little script and having trouble
> > comparing integers and decimal numbers. The shell doesn't
> > like it and I haven't been able to figure out how to get
> > around it. Script is named zyx.
> >
> > 1 #!/bin/sh
> > 2 ADMINA="[email protected]"
> > 3 dt=`date '+%a %b %e %I:%M %p' `
> > 4 svr=`hostname`
> > 5 ALERT=75
> > 6 mpstat | grep -i all |awk '{print $4}'|
> > 7 while read output;
> > 8 do
> > 9 cpuutil=`(echo $output | awk '{ print $1}' | cut
> -d'%' -f1 )`
> > 10 set -x
> > 11 if [ "$cpuutil" -ge $ALERT ]; then
> > 12 echo "CPU utilization has risen beyond the alert
> > threshold on $svr at $dt"| mail -vs "Alert:- CPU utilization
> > is hi gh on $svr at $dt" $ADMINA
> > 13 fi
> > 14 done
> >
> > xyz
> > + '[' 3.19 -ge 75 ']'
> > /usr/sbin/xyz: line 11: [: 3.19: integer expression expected
> > + read output
> >
> > mpstat is returns 3.19 and I'm trying, on line 11, to compare
> > that to ALERT which is set to 75. I think I need to strip off
> > the decimal part of 3.19 but haven't found any way to do it.
> >
> >
> > Bobby Bauer
> > Center for Information Technology
> > National Institutes of Health
> > Bethesda, MD 20892-5628
> > 301-594-7474
> >
> >
> >
> >
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> ----------------------------------------------------------------------
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> >
> >
> ----------------------------------------------------------------------
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>
> ----------------------------------------------------------------------
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> send email to [email protected] with the message: INFO
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>
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