You mean like Ksh's discipline functions? dualbus@system76-pc:~$ ksh -c 'date=; date.get() { .sh.value=$(date +%s); }; echo $date; sleep 5; echo $date' 154

You mean like Ksh's discipline functions? dualbus@system76-pc:~$ ksh -c 'date=; date.get() { .sh.value=$(date +%s); }; echo $date; sleep 5; echo $date' 1546926637 1546926642 See: https://docs.oracle.com/cd/E36784_01/html/E36870/ksh-1.html https://docs.oracle.com/cd/E36784_01/html/E36870/ksh-1.html ("Discipline Functions")