UNIX for Dummies Questions & Answers

bash-3.00$ date

start=`date +"%T" | awk -F":" '{print $2,$3}'`
echo $start
08 17
end=`date +"%T" | awk -F":" '{print $2,$3}'`
echo $end
08 37

bash-3.00$ echo `expr $end - $start`
expr: syntax error

bash-3.00$ echo  $(($end - $start))
bash: 08: value too great for base (error token is "08")

end=( $(date +"%T") )
echo ${end[@]}
15 50 54
start='15 08 01'
echo $(( (10#${end[0]} - 10#${start[0]}) * 3600 + (10#${end[1]} - 10#${start[1]}) * 60 + 10#${end[2]} - 10#${start[2]} ))
2573

START=`date +"%T" | awk -F":" '{print $2 FS $3}'`
##### I ran following command after few mins
END=`date +"%T" | awk -F":" '{print $2 FS $3}'`
##### Then use following awk command to calculate difference.
awk -vstart=$START -vend=$END 'BEGIN{split(start, A,":");split(end, B,":");sec_start=A[1] * 60 + A[2];sec_end=B[1] * 60 + B[2];diff=sec_end - sec_start;print "Minutes \t Seconds" ORS int(diff/60) "\t\t " diff%60}'

#!/usr/bin/ksh
START="$(date +%s";"%T)"
sleep 2 # this is your job, my job is sleeping.
END="$(date +%s";"%T)"
printf "From=%s To=%s Dur=%s sec\n" "${START#*;}" "${END#*;}"  "$((${END%%;*}-${START%%;*}))"

# time <command>
real    0m3.01s
user    0m0.00s
sys     0m0.00s

START=$SECONDS 
... commands ... 
echo $(( SECONDS - START ))
31

 START=`date +"%T" | awk -F":" '{print $2 FS $3}'`
 echo $START
31:36
 END=`date +"%T" | awk -F":" '{print $2 FS $3}'`
 echo $END
31:59
 awk -vstart=$START -vend=$END 'BEGIN{split(start, A,":");split(end, B,":");sec_start=A[1] * 60 + A[2];sec_end=B[1] * 60 + B[2];diff=sec_end - sec_start;print "Minutes \t Seconds" ORS int(diff/60) "\t\t " diff%60}'
Minutes          Seconds
0                0

uname -a
SunOS 5.10 Generic_148888-05 sun4u sparc SUNW,SPARC-Enterprise