Custom format for time command

user_439621 0
Viewed 135990

I'd like to use the time command in a bash script to calculate the elapsed time of the script and write that to a log file. I only need the real time, not the user and sys. Also need it in a decent format. e.g 00:00:00:00 (not like the standard output). I appreciate any advice.

The expected format supposed to be 00:00:00.0000 (milliseconds) [hours]:[minutes]:[seconds].[milliseconds]

I've already 3 scripts. I saw an example like this:

{ time { # section code goes here } } 2> timing.log

But I only need the real time, not the user and sys. Also need it in a decent format. e.g 00:00:00:00 (not like the standard output).

In other words, I'd like to know how to turn the time output into something easier to process.

format shell time bash
6 Answers

Use the bash built-in variable SECONDS. Each time you reference the variable it will return the elapsed time since the script invocation.

Example:

echo "Start $SECONDS"
sleep 10
echo "Middle $SECONDS"
sleep 10
echo "End $SECONDS"

Output: 

Start 0
Middle 10
End 20
user_12668970

The accepted answer gives me this output

# bash date.sh
Time in seconds: 51
date.sh: line 12: unexpected EOF while looking for matching `"'
date.sh: line 21: syntax error: unexpected end of file

This is how I solved the issue

#!/bin/bash

date1=$(date --date 'now' +%s) #date since epoch in seconds at the start of script
somecommand
date2=$(date --date 'now' +%s) #date since epoch in seconds at the end of script
difference=$(echo "$((date2-$date1))") # difference between two values
date3=$(echo "scale=2 ; $difference/3600" | bc) # difference/3600 = seconds in hours
echo SCRIPT TOOK $date3 HRS TO COMPLETE # 3rd variable for a pretty output.
user_115802320
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