$ cat in.txt
1 22 3 -4
a
b c
d e f
g h i j
k l m n o
$ perl -anle 'print "@F[map $#F-$_*2, 0..$#F/2]"' in.txt
-4 22
a
c
f d
j h
o m k
But seriously, there are lots of ways to do this. Just one of many:
while (<>) {
my @fields = split;
for (my $i=$#fields; $i>=0; $i-=2) {
print "$fields[$i] ";
}
print "\n";
}
Update: As for your code, I'd probably have used for instead of map, but other than that it's a decent solution. Just for fun, a different way to write that might be: ++$i&1 and print "$_ " for reverse split; although that might be getting a little too clever ;-) This is a fun exercise in TIMTOWTDI! Update 2: Changed wording a bit.
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