The unix time stamp is a way to track time as a running total of seconds.
Unix timestamp wall clock.
Therefore the unix time stamp is merely the number of seconds between a particular date and the unix epoch.
Week numbers weeks by year day numbers days by year years leap years calculate the difference between two dates.
To compare two dates in bash you can use the unix timestamp value of both date using the date command line or the printf method and a bash if statement with a bash arithmetic expansion or by using a lexicographical comparison of the two dates string by using the double square bracket conditional construct.
Date and time.
The year 2038 problem also called y2038 epochalypse y2k38 or unix y2k relates to representing time in many digital systems as the number of seconds passed since 00 00 00 utc on 1 january 1970 and storing it as a signed 32 bit integer such implementations cannot encode times after 03 14 07 utc on 19 january 2038.