#        1         2         3         4
#23456789012345678901234567890123456789012345
perl -lne'$a[$.].=$_;$.=0if eof}{print for@a'


##</code><code>##

   $. is reset when the filehandle is closed, but not when an open
   filehandle is reopened without an intervening close().  For
   more details, see "I/O Operators" in perlop.  Because "<>"
   never does an explicit close, line numbers increase across ARGV