pass variable as sar argument

Shell Programming and Scripting
1

I am trying to get the details of iowait for last hour using sar. When I give date as argument it works.

# sar -u -s 22:24:00 -e 23:24:00
Linux 2.6.35.13-26 (XX.server.com)   04/11/2012

10:30:03 PM       CPU     %user     %nice   %system   %iowait     %idle
10:40:04 PM       all      5.03      0.01      3.20     48.95     42.81
10:50:04 PM       all      3.58      0.02      3.88     56.53     36.00
Average:          all      4.30      0.02      3.53     52.74     39.41

10:58:34 PM       LINUX RESTART

11:10:01 PM       CPU     %user     %nice   %system   %iowait     %idle
11:20:01 PM       all      4.72      4.17      2.02     39.23     49.86
Average:          all      4.72      4.17      2.02     39.23     49.86

But when I pass hour and minute as variable it does not work. Variable contain the correct value.

# currhour=`date | awk {'print $4'} | cut -d: -f 1` ; currmin=`date | awk {'print $4'} | cut -d: -f 2`;  lasthour=`expr $currhour - 01` ; lasthour=`printf %02d $lasthour` ; sar -u -s $currhour:$currmin:00 -e $lasthour:$currmin:00
Linux 2.6.35.13-26 (XX.server.com)   04/11/2012

Variable outout

# currhour=`date | awk {'print $4'} | cut -d: -f 1` ; currmin=`date | awk {'print $4'} | cut -d: -f 2`;  lasthour=`expr $currhour - 01` ; lasthour=`printf %02d $lasthour` ; echo -e "currhour $currhour \n" ; echo -e "currmin $currmin \n" ; echo -e "lasthour $lasthour \n"

currhour 23

currmin 57

lasthour 22
2

Please show us the lines where you create the parameters for sar and create the sar command line.
Please post what happens when it does not work.

Forget that, just found the command 3 feet off the right of the screen!

sar -u -s $currhour:$currmin:00 -e $lasthour:$currmin:00

There are quotes missing and (more importantly) the start and end are reversed:

sar -u -s "$lasthour:$currmin:00" -e "$currhour:$currmin:00"

Footnote:
Wherever you have a semicolon you could start a new line instead and make it so much easier to read.

3

Try in this way

 
sar -u -s $(date +%H:%M:%S --date=-1hour) -e $(date +%H:%M:%S)