perl -MList::Util=first -e 'sub a { my $a; first { $a } 0}; a() while 1'

$ vm `pgrep -f List::Util`
VmSize:    53940 kB
VmSize:    85884 kB
VmSize:   117564 kB

alias vm='perl -e '\''do{ print `grep VmSize /proc/$ARGV[0]/status` }while(sleep(1))'\'''