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I have some data spread over time intervals, and I want to take some of those data within the time intervals. For example, I have data at times within 1..9, 11..19, etc., and I want to take data within 1-2, then 11-12, etc. This will be part of a more complex bash script, in which I want to include this condition, with a if cycle, to isolate the times where I can catch the data.

I was thinking something like:

if (( $t_initial & $t_final )) in (begin1, fin1) or in (begin2, fin2) ...

where t_initial and t_final are calculated separately, by the script itself.

I can not write this condition in bash syntax. I found some other solutions, but they seem extremely long and inconvenient, so I am here to ask simpler and more readable solutions.

share|improve this question
    
I don't get it. Data should have a single timestamp, why do you have 2 variables t_initial and t_final? –  LatinSuD Jun 27 at 9:18
    
@LatinSuD, Because I am working in phase, more than times, and I have to get only same phase intervals between given time intervals :) –  Py-ser Jun 27 at 9:26
    
What happens if t_initial=1, t_final=3, begin1=2,fin1=4? Is that a match or not? –  LatinSuD Jun 27 at 9:27
    
@LatinSuD, no it is not. begin and fin are intended to be the extreme times of a given interval. if the times are not within the intervals, then the condition is not satisfied. –  Py-ser Jun 27 at 9:29
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1 Answer

up vote 0 down vote

Not sure if you would like this solution. It has 2 features:

  • No external programs are required
  • It uses a function, so at least it hides the complexity of the comparisons

This is it:

#!/bin/bash

# The comparing function
function compareInterval {
 t1=$1
 t2=$2

 shift 2

 while (( "$2" )); do
   if ((  $t1 >= $1  &&  $t2 <= $2 )); then
     # got match
     return 0
   fi
   shift 2
 done

 return 1
}

# sample values
t_initial=2
t_final=4

# Invocation. Compares against 1-3, 3-5, 2-5
if compareInterval  $t_initial $t_final  1 3  3 5  2 5; then
 echo Got match
fi
share|improve this answer
    
Thanks a lot! I have never used functions in bash, could you tell me the logic behind the separation of the comparison? how can it understand to compare between 1 and 3, and not between, i.e., 3 and 3, or 5 and 2 (in the example above)? –  Py-ser Jun 27 at 10:50
    
Separation is cosmetic only. The important thing is parameter number. They are processed in pairs. –  LatinSuD Jun 27 at 11:01
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