Using current timestamp at command line

Question

I have this command that works as expected:

aws cloudwatch get-metric-statistics \
    --region ap-south-1 \
    --namespace AWS/RDS \
    --metric-name DBLoad  \
    --period 60 \
    --statistics Average \
    --start-time 2023-06-12T01:00:00Z \
    --end-time 2023-06-12T23:00:00Z \

But I wish I could write something like this...

    --start-time now() - 12 hours \
    --end-time now() \

Is it possible to use now() in shell?

_Which_ shell? Have you read e.g. https://stackoverflow.com/q/5934394/3001761? — jonrsharpe, Jun 12 '23 at 11:23
No. However, you can write your customized shell script. Check this post - https://stackoverflow.com/questions/6467/date-arithmetic-in-unix-shell-scripts. — madD7, Jun 12 '23 at 11:23

Jiraiya · Accepted Answer · 2023-06-12T12:07:10.127

2

You can use it in following way

    --start-time $(date -u -d '12 hour ago' +%Y-%m-%dT%H:%M:%SZ) \
    --end-time $(date -u +%Y-%m-%dT%H:%M:%SZ) \

Hope this helps.

edited Jun 12 '23 at 12:07

answered Jun 12 '23 at 11:21

Jiraiya

52
7

Technically, you should also single quote the `date` format string, e.g. `+'....'` – David C. Rankin Jun 12 '23 at 11:56
Won't this give you a _local datetime_ that's formatted as if it's in UTC? – jonrsharpe Jun 12 '23 at 12:03
@jonrsharpe I have edited as per your suggestion. – Jiraiya Jun 12 '23 at 12:07

Using current timestamp at command line

1 Answers1