How to get yesterday time

Sometimes, we need to create a simple script in linux which involves retrieving system time several days/hours/minutes ago.

Belows are example use of date command:

To get yesterday time:

$ date --date="1 days ago"

or

$ date --date="-1 days"

To get one month ago:

$ date --date="1 months ago"

or

$ date --date="-1 months"

To get one hour ago:

$ date --date="1 hours ago"

or

$ date --date="-1 hours"

To get one minutes in the future:

$ date --date="+1 minutes"

To get one seconds in the future:

$ date --date="+1 seconds"

We can also combine it, example to get one month and two hours ago:

$ date --date="1 month 2 hours ago"

or

$ date --date="-1 month -2 hours"

There are many other ways to express the particular time.

That's all :)