A lot of tools and systems use a Unix timestamp to represent a point in time.
It is the number of seconds since the Unix epoch (Jan 1, 1970). However, just
looking at a timestamp like 1623867544 doesn't tell a human much. I can't
mentally translate that to the date and time that it is representing.
The date utility can help. Give it the -r flag with the timestamp value (in
seconds) and it will display the date and time in a human-readable format.
❯ date -r '1623867544'
Wed Jun 16 13:19:04 CDT 2021See man date for more details.