CODEWITHSUNDEEP
bash
bullfighter
bullfighter

Reputation: 427

Loop to iterate given time by 1 hour

I am splitting a 24-hour timeframe API call into an hourly one. I need to create time intervals like 00:00-01:00, 01:00-02:00, ... and assign them to variables start_time and stop_time to be used in the call.

Got this so far:

date=$'20210825'

for i in {0..23}
    
    start_time=$(date -d $date "+ "$i"hour" +%s)"000"
    stop_time=$(date -d $date "+ "$i+1"hour" +%s)"000"
    
    echo $start_time
    echo $stop_time
    
    API call happens here inside for loop

But it complains about syntax error. Any ideas on how to correctly increment the variables?

Upvotes: 0

Views: 487

Answers (3)

tripleee
tripleee

Reputation: 189417

As long as the time intervals are within the same day, there is no need to call date multiple times. Just call it once to get the baseline, then add to that.

baseline=$(date -d 2021-08-25 +%s)

for((i=0; i<24*3600; i += 3600)); do
    start_time=$((baseline+i))"000"
    stop_time=$((baseline+i+3600))"000"
    printf '%s\n' "$start_time" "$stop_time"
done

I'm wondering if the stop time shouldn't be the start time plus 3599.999, though.

This "C-style" for loop syntax is a Bash extension, and not portable to POSIX sh etc.

Upvotes: 0

Gonzalo Matheu
Gonzalo Matheu

Reputation: 10064

This is what I did in the past for similar scenario:

year='2021'
month='08'
date='25'
for i in {0..23}
do
    end=$(($i + 1))
    start_time=$(date -v ${year}y -v ${month}m -v${date}d -v${i}H -v0M -v0S +%s)"000"
    stop_time=$(date -v ${year}y -v ${month}m -v${date}d -v${end}H -v0M -v0S +%s)"000"

    echo $start_time
    echo $stop_time
done
  • Added do / done statements to for loop
  • Used -v to adjust each date part

Upvotes: 1

0stone0
0stone0

Reputation: 43983

You can use the following date format:

start_time=$(date -d "${date} + ${i} hour" +%s)"000"

The +1 can be done using the $((...)) syntax:

"${date} + $((i + 1)) hour"

So the script becomes:

date=$'20210825'

for i in {0..23}; do
    
    start_time=$(date -d "${date} + ${i} hour" +%s)"000"
    stop_time=$(date -d "${date} + $((i + 1)) hour" +%s)"000"
    
    echo $start_time
    echo $stop_time
    echo -e
done

Try it online!

Output:

1629849600000
1629853200000

1629853200000
1629856800000

1629856800000
1629860400000

1629860400000
1629864000000

1629864000000
1629867600000

1629867600000
1629871200000

1629871200000
1629874800000

1629874800000
1629878400000

1629878400000
1629882000000

1629882000000
1629885600000

1629885600000
1629889200000

1629889200000
1629892800000

1629892800000
1629896400000

1629896400000
1629900000000

1629900000000
1629903600000

1629903600000
1629907200000

1629907200000
1629910800000

1629910800000
1629914400000

1629914400000
1629918000000

1629918000000
1629921600000

1629921600000
1629925200000

1629925200000
1629928800000

1629928800000
1629932400000

1629932400000
1629936000000

Upvotes: 2

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