• now ?(-mac|-abs)?
Return the current time in seconds. If no argument is specified, it is the number of seconds that have elapsed since January 1 1970 00:00:00 GMT (aka the Unix epoch): this value is suitable for use with Alpha's [mtime] command and with Tcl's [file atime] and [file mtime] commands.
With the -mac option, it is the number of seconds since Midnight Jan 1, 1904 (aka the Mac epoch). With the -abs option, it is the time measured in seconds relative to the absolute reference date of Jan 1 2001 00:00:00 GMT.