^start of line
Group 1((\d|\*(/\d{1,2})?)\s){5} {5}repeats the group contents below exactly 5 times:
Group 2(\d|\*(/\d{1,2})?) 2nd Alternative\*(/\d{1,2})? \*the literal * (4210 / 528 / 2A16)
?repeats the group contents below at most once:
/the literal / (4710 / 578 / 2F16)
\d{1,2}a digit, repeated between 1 and 2 times
\sany whitespace character
http://wwwthe literal text http://www (case sensitive) .any character (except for line terminators)
\S+any non-whitespace character, repeated at least once
/the literal / (4710 / 578 / 2F16)
.+any character (except for line terminators), repeated at least once
doing_wp_cronthe literal text doing_wp_cron (case sensitive) \sany whitespace character
>/dev/nullthe literal text >/dev/null (case sensitive) \sany whitespace character
2>&1the literal text 2>&1 $end of line
g modifier: global. Finds all matches instead of stopping after the first
m modifier: multiline. Causes ^ and $ to match the start and end of each line, not only the start and end of the string