you could ask why have sub/gsub when there is sed... that's because you need that for specific field or string in addition to other processing.. similarly, having tr for specific string/field is useful..

I meant join as in perl's join - to construct a string out of array values with specified separator

Some examples:

* https://stackoverflow.com/questions/48920626/sort-rows-in-cs...

* https://stackoverflow.com/questions/45571828/execute-bash-co...

* https://stackoverflow.com/questions/48925359/sorting-groups-...