OS-variables in awk

kielhd

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Apr 22, 2009, 8:42:45 AM4/22/09

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Hi NG,

I am experiencing problems with a little awk-script:

...
### DISK ###
DISK=`/usr/bin/df -k |\
sed -n '/^\/dev/p' |\
awk '{ USED = substr($4,1,length($4)-1); \
{ STATUS = "good" }
if ( USED > "'"$SCHWELL1"'" ) { STATUS = "warning" }
if ( USED > "'"$SCHWELL2"'" ) { STATUS = "error" }
printf "%s - %s,%s ; (%s) %s_used; %u MB_free; %u MB_total;\n", USED,
STATUS, STATUS, $7, $4, $3/1024, $2/1024}'`
...

The variable USED contains a numeric value (e.g. 9) and is compared to
the values of $SCHWELL1 (e.g. 85) and $SCHWELL2 (e.g. 90), which are
os-variables.

The outout of the script shows an error in the marked line
(<<<------):

18 - good,good ; (/) 18%_used; 840 MB_free; 1024 MB_total;
21 - good,good ; (/usr) 21%_used; 13033 MB_free; 16384 MB_total;
17 - good,good ; (/var) 17%_used; 856 MB_free; 1024 MB_total;
13 - good,good ; (/tmp) 13%_used; 896 MB_free; 1024 MB_total;
66 - good,good ; (/home) 66%_used; 352 MB_free; 1024 MB_total;
73 - good,good ; (/opt) 73%_used; 70 MB_free; 256 MB_total;
63 - good,good ; (/install) 63%_used; 9708 MB_free; 25600 MB_total;
86 - warning,warning ; (/mysqlbackup) 86%_used; 46396 MB_free; 327936
MB_total;
9 - warning,warning ; (/mysqldata1) 9%_used; 138602 MB_free; 151296
MB_total; <<<------
89 - warning,warning ; (/mysqldata2) 89%_used; 27036 MB_free; 227072
MB_total;
56 - good,good ; (/mysqllog) 56%_used; 33898 MB_free; 75520 MB_total;
32 - good,good ; (/mysqltemp) 32%_used; 34294 MB_free; 50176 MB_total;
4 - good,good ; (/mksysb) 4%_used; 67404 MB_free; 69632 MB_total;

I expect the STATUS to be "good", not "warning".

Any ideas?

TIA,
Henning

pmarin

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Apr 22, 2009, 9:59:21 AM4/22/09

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I think that If you use single quotes in the body of the program awk
'{ }' you are preventing of shell variable subtitution.

Message has been deleted

pmarin

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Apr 22, 2009, 10:07:48 AM4/22/09

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Use variable arguments: awk -v

### DISK ###
DISK=`/usr/bin/df -k |\
sed -n '/^\/dev/p' |\

awk -v shwell1 = $SCHELL1 -v shwell2 = $SCHWELL2 '{ USED = substr
($4,1,length($4)-1); \
{ STATUS = "good" }
if ( USED > shwell1 ) { STATUS = "warning" }
if ( USED > shwell2 ) { STATUS = "error" }

Hermann Peifer

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Apr 22, 2009, 10:55:22 AM4/22/09

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Hermann Peifer

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Apr 22, 2009, 11:02:37 AM4/22/09

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On Apr 22, 4:07 pm, pmarin <pacog...@gmail.com> wrote:
>

> Use variable arguments: awk -v
> ### DISK ###
> DISK=`/usr/bin/df -k |\
> sed -n '/^\/dev/p' |\
> awk -v shwell1 = $SCHELL1 -v shwell2 = $SCHWELL2 '{ USED = substr
> ($4,1,length($4)-1); \
> { STATUS = "good" }
> if ( USED > shwell1 ) { STATUS = "warning" }
> if ( USED > shwell2 ) { STATUS = "error" }
> printf "%s - %s,%s ; (%s) %s_used; %u MB_free; %u MB_total;\n", USED,
> STATUS, STATUS, $7, $4, $3/1024, $2/1024}'`

One could also get rid of sed and include this part into the AWK
script

USED = substr($4,1,length($4)-1) could be replaced by USED = $4 + 0

The assignment for STATUS could be simplified to:

STATUS = USED > shwell2 ? "error" :
USED > shwell1 ? "warning" : "good"

Hermann

Steffen Schuler

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Apr 22, 2009, 12:42:46 PM4/22/09

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-----BEGIN PGP SIGNED MESSAGE-----
Hash: SHA1

On 2009-04-22, kielhd <kie...@freenet.de> wrote:
> [...]

> I am experiencing problems with a little awk-script:
>
> ...
> ### DISK ###
> DISK=`/usr/bin/df -k |\
> sed -n '/^\/dev/p' |\
> awk '{ USED = substr($4,1,length($4)-1); \
> { STATUS = "good" }
> if ( USED > "'"$SCHWELL1"'" ) { STATUS = "warning" }
> if ( USED > "'"$SCHWELL2"'" ) { STATUS = "error" }
> printf "%s - %s,%s ; (%s) %s_used; %u MB_free; %u MB_total;\n", USED,
> STATUS, STATUS, $7, $4, $3/1024, $2/1024}'`
> ...
>
> The variable USED contains a numeric value (e.g. 9) and is compared to
> the values of $SCHWELL1 (e.g. 85) and $SCHWELL2 (e.g. 90), which are
> os-variables.
>
> The outout of the script shows an error in the marked line
> (<<<------):
>

> [...]

> 9 - warning,warning ; (/mysqldata1) 9%_used; 138602 MB_free; 151296
> MB_total; <<<------

> [...]

>
> I expect the STATUS to be "good", not "warning".

Hi,

you do a string compare instead of a numeric compare, when you compare
USED to $SCHWELLn for n = 1, 2. Add zero to both string variables inside
of awk and you get the correct result, e.g.

USED + 0 > "'"$SCHWELL1"'" + 0

to force a numeric interpretation.

(As the other posters said, use better the awk option -v var=val on the
command line to pass OS variables to awk.)

Kind regards,

Steffen

- --
Steffen Schuler (goedel) <schuler...@gmail.com>
Key ID: 0x42C5D853 / Key-server: pgp.mit.edu
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r.p....@gmail.com

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Apr 22, 2009, 6:00:32 PM4/22/09

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Is this any cleaner? I added the output of our df -k since it differs
from yours. You can call this with "awk -f u -v SCHWELL1=85"

loui@euclid:/tmp$ less u
#Filesystem 1K-blocks Used Available Use% Mounted on
#/dev/sdb2 19380708 13560240 4843716 74% /
#varrun 6187596 84 6187512 1% /var/run
#varlock 6187596 0 6187596 0% /var/lock
#udev 6187596 52 6187544 1% /dev
#devshm 6187596 0 6187596 0% /dev/shm
#mozart.bio.ri.cia.gov:/export/home/studies
# 181540440 168094816 11630216 94% /studies
#mozart.bio.ri.cia.gov:/export/home/programs
# 181540440 168094816 11630216 94% /programs
#mozart.bio.ri.cia.gov:/export/home/vol
# 181540440 168094816 11630216 94% /vol
#/dev/sdb1 93307 24205 64285 28% /boot
#/dev/sdb3 58134488 9333924 45870712 17% /opt
#/dev/sda1 968841096 122203764 797810580 14% /var
#mozart:/export/home/home/chana3
# 181540864 168094720 11630592 94% /home/chanb7

BEGIN {
if ("" == SCHWELL1) SCHWELL1 = 50
if ("" == SCHWELL2) SCHWELL2 = 90
com = "df -l -k"
com | getline
while (com | getline) {
if ($1 !~ /^\/dev/) continue
USED = $5; sub(/.$/,"",$5)
printf "%s - ", $5
STATUS = (USED > SCHWELL1) ? "warning" : "good"
STATUS = (USED > SCHWELL2) ? "error" : STATUS
printf "%s,%s ; ", STATUS, STATUS
printf "(%s) ", $6
printf "%s_used; ", $5
printf "%s MB_free; ", $4/1024
printf "%s MB_total; ", $2/1024
print ""
}
}

kielhd

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Apr 23, 2009, 2:09:44 AM4/23/09

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> Steffen Schuler (goedel) <schuler.stef...@gmail.com>

> Key ID: 0x42C5D853 / Key-server: pgp.mit.edu
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> - Zitierten Text anzeigen -

Your hint solved my problem, thank you and all the other posters!
Best regards,
Henning

Ed Morton

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Apr 23, 2009, 9:40:32 AM4/23/09

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I've no idea if the above works or not but if you'd prefer to have it
written in awk:

BEGIN {
if ("" == SCHWELL1) SCHWELL1 = 50
if ("" == SCHWELL2) SCHWELL2 = 90
}

(NR > 1) && ($1 !~ /^\/dev/) {

USED = $5; sub(/.$/,"",$5)
printf "%s - ", $5
STATUS = (USED > SCHWELL1) ? "warning" : "good"
STATUS = (USED > SCHWELL2) ? "error" : STATUS
printf "%s,%s ; ", STATUS, STATUS
printf "(%s) ", $6
printf "%s_used; ", $5
printf "%s MB_free; ", $4/1024
printf "%s MB_total; ", $2/1024
print ""
}

Ed.