Esa navaja suiza antes conocida como "date"

GNU date is one of the many common Linux programs in GNU Coreutils package. Here are some of the examples of performing date time arithmetic with GNU date command, using -d or --date option switch:

date -d "last month" +%m

Return as last month in numeric format

date -d "2 month ago" +%b

Return as last month in abbreviated month name

date -d "-2 month" +%B

Return as last month in full month name

date -d "-1 hours" +%H

Returns previous hour in 24-hours format (00-23)

date -d "tomorrow"

Return the date and time of tomorrow

date -d "yesterday" +"%d %B %y"

Return the date of yesterday in dd MMM yy

date -d "last week" +%a

Return last week in abbreviated weekday name

date -d "$(date +%Y-%m-15) -1 month" +'Last month was %B!'

To avoid getting result of “July” when executing date -d "-1 month" +%B on 31 July 2006, because “2006-07-31 -1 month” might evaluate to 2006-07-01, because 2006-06-31 is an invalid date!

date -d "1970-01-01 00:00:01 UTC" +%s

Return the Unix Epoch time (the total seconds elapse since midnight of 1970-01-01), which is 1 secs in this case.

date -d "1970-01-01 1234567890 sec" +"%F %T %z"

Return the literal date format of the given Unix Epoch time.