Question

I’m trying to create an awk script to subtract milliseconds between 2 records joined-up for example:

By command line I might do this:

Input:

06:20:00.120
06:20:00.361
06:20:15.205
06:20:15.431
06:20:35.073
06:20:36.190
06:20:59.604
06:21:00.514
06:21:25.145
06:21:26.125

Command:

awk '{ if ( ( NR % 2 ) == 0 ) { printf("%s\n",$0) } else { printf("%s ",$0) } }' input 

I’ll obtain this:

06:20:00.120 06:20:00.361
06:20:15.205 06:20:15.431
06:20:35.073 06:20:36.190
06:20:59.604 06:21:00.514
06:21:25.145 06:21:26.125

To substract milliseconds properly:

awk '{ if ( ( NR % 2 ) == 0 ) { printf("%s\n",$0) } else { printf("%s ",$0) } }' input| awk -F':| ' '{print $3, $6}'

And to avoid negative numbers:

awk '{if ($2<$1) sub(/00/, "60",$2); print $0}'
awk '{$3=($2-$1); print $3}'

The goal is get this:

Call 1 0.241 ms
Call 2 0.226 ms
Call 3 1.117 ms
Call 4 0.91 ms
Call 5 0.98 ms

And finally and average.

I might perform this but command by command. I dunno how to place this into a script.

Please need help.

Answer 1

One way using awk:

Content of script.awk:

## For every input line.
{
        ## Convert formatted dates to time in miliseconds.
        t1 = to_ms( $0 )
        getline
        t2 = to_ms( $0 )

        ## Calculate difference between both dates in miliseconds.
        tr = (t1 >= t2) ? t1 - t2 : t2 - t1

        ## Print to output with time converted to a readable format.
        printf "Call %d %s ms\n", ++cont, to_time( tr )
}

## Convert a date in format hh:mm:ss:mmm to miliseconds.
function to_ms(time,    time_ms, time_arr)
{
        split( time, time_arr, /:|\./ )
        time_ms = ( time_arr[1] * 3600 + time_arr[2] * 60 + time_arr[3] ) * 1000 + time_arr[4]
        return time_ms
}


## Convert a time in miliseconds to format hh:mm:ss:mmm. In case of 'hours' or 'minutes'
## with a value of 0, don't print them.
function to_time(i_ms,         time)
{
        ms = int( i_ms % 1000 )
        s = int( i_ms / 1000 )
        h = int( s / 3600 )
        s = s % 3600
        m = int( s / 60 )
        s = s % 60
#       time = (h != 0 ? h ":" : "")  (m != 0 ? m ":" : "") s "." ms
        time = (h != 0 ? h ":" : "")  (m != 0 ? m ":" : "") s "." sprintf( "%03d", ms )
        return time
}

Run the script:

awk -f script.awk infile

Result:

Call 1 0.241 ms
Call 2 0.226 ms
Call 3 1.117 ms
Call 4 0.910 ms
Call 5 0.980 ms