Just print the message from the background process: 
system '( nohup sleep 5 ; echo Shell done. ) &';
print "Perl done.\n";

[download]
Beware: The message can appear in the middle of the command line. Precede it with a newline to prevent it, but it can still do weird things if you e.g. run mc in the meantime.

($q=q:Sq=~/;[c](.)(.)/;chr(-||-|5+lengthSq)`"S|oS2"`map{chr |+ord
}map{substrSq`S_+|`|}3E|-|`7**2-3:)=~y+S|`+$1,++print+eval$q,q,a,

[download]

In reply to Re: Executing a command after the preceding command finished processing by choroba
in thread Executing a command after the preceding command finished processing by Locutus_

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