Calculate the Time difference in bash Script

Question

I need to calculate the time difference between RMAN start and RMAN End. Log is like this

-rw-r----- oracle/dba 2017-03-11 21:56:35 storage/backup/daily/ALG_PDB_2drut5jf.alg
-rw-r----- oracle/dba 2017-03-11 21:56:34 storage/backup/daily/ALG_PDB_2erut5jf.alg
-rw-r----- oracle/dba 2017-03-11 21:56:07 storage/backup/daily/ALG_PDB_2frut5jf.alg
-rw-r----- oracle/dba 2017-03-11 21:56:29 storage/backup/daily/ALG_PDB_2grut5jv.alg
-rw-r----- oracle/dba 2017-03-11 21:39:14 storage/backup/daily/BKPPDB_28rut42s.F_bkp
-rw-r----- oracle/dba 2017-03-11 21:47:28 storage/backup/daily/BKPPDB_29rut42s.F_bkp
-rw-r----- oracle/dba 2017-03-11 21:42:41 storage/backup/daily/BKPPDB_2arut42s.F_bkp
-rw-r----- oracle/dba 2017-03-11 21:55:33 storage/backup/daily/BKPPDB_2brut4k8.F_bkp
-rw-r----- oracle/dba 2017-03-11 21:55:36 storage/backup/daily/c-2819904582-20170311-00
-rw-r----- oracle/dba 2017-03-11 21:56:42 storage/backup/daily/c-2819904582-20170311-01
-rw-r----- oracle/dba 2017-03-11 21:56:41 storage/backup/daily/control_PDB_2hrut5kp.ctl

I wrote a script that first sort the column based on 4th column which is Time , Below is the script

#!/bin/bash -x
if [ -f /storage/backup/weekly/DB-Backup-$(date -d "yesterday" '+%a-%d%m%y').tgz ]
 then

export StartMin=$(tail -30 /storage/backup/weekly/DailyCompressionLog|grep "^-\|^ -" |sort -k5|awk '{print $5}' |awk -F ":" '{print $2}'|awk 'NR==1; END{print}'|awk 'FNR==1 {print $1}')
export EndMin=$(tail -30 /storage/backup/weekly/DailyCompressionLog|grep "^-\|^ -" |sort -k5|awk '{print $5}' |awk -F ":" '{print $2}'|awk 'NR==1; END{print}'|awk 'FNR==2 {print $1}')

export StartHour=$(tail -30 /storage/backup/weekly/DailyCompressionLog|grep "^-\|^ -" |sort -k5|awk '{print $5}' |awk -F ":" '{print $1}'|awk 'NR==1; END{print}'|awk 'FNR==1 {print $1}')
export EndHour=$(tail -30 /storage/backup/weekly/DailyCompressionLog|grep "^-\|^ -" |sort -k5|awk '{print $5}' |awk -F ":" '{print $1}'|awk 'NR==1; END{print}'|awk 'FNR==2 {print $1}')

echo "Backup for `date -d "yesterday" '+%a-%d%m%y'`" >> /storage/backup/weekly/MonthlyCompressionLog
echo -e "RMAN Backup Started at $StartHour":"$StartMin" >> /storage/backup/weekly/MonthlyCompressionLog
echo -e "RMAN Backup Ended   at $EndHour":"$EndMin" >> /storage/backup/weekly/MonthlyCompressionLog
echo -e "Time taken to Complete Backup Job Hours:Mins $((EndHour-StartHour))":"$((EndMin-StartMin))" >> /storage/backup/weekly/MonthlyCompressionLog

echo -e "-------------------------------------------------------\n" >> /storage/backup/weekly/MonthlyCompressionLog

When Script works (Success)

If End Time is Greater Than StartTime

When Script Fails

In current state if the Start Time is great than End Time , In this case Endhour will be greater than the StartHour

Scenario :: Lets say if RMAN started at 14:56 and completes at 15:02 , In this case total Time from Start to End is just 00:06 Min but script will show 1:-54

Any ideas ....

The text you have posted on top, is that the output of `ls`? — codeforester, Mar 12 '17 at 07:55

score 1 · Answer 1 · edited May 23 '17 at 12:17

Instead of calculating Hours and Minutes separately, calculate the number of minutes since midnight for Start and End, and perform arithmentic using that.

So something like :

StartNumMins=$(( $StartHour * 60 + $StartMin ))
EndNumMinutes=$(( $EndHour * 60 + $EndMin ))

MinutesDiff=$(( $EndNumMinutes - $StartNumMins ))

DiffHours="0$(($MinutesDiff / 60))"
DiffMins="0$(($MinutesDiff % 60))"

echo "Diff is $MinutesDiff minutes, which is ${DiffHours:-2}:${DiffMins:-2}"

which produces :

Diff is 6 minutes, which is 00:06

Of course, if your process crosses midnight, then you'll have to take the start/end dates into consideration, not just the times. There are a few options to do that (such as using GNU's 'date' if that's available to you - eg. see Convert an ISO date to seconds since epoch in linux bash ), but that's another issue.

Calculate the Time difference in bash Script

When Script works (Success)

When Script Fails

1 Answers1