From perldoc -f localtime,

#  0    1    2     3     4    5     6     7     8
($sec,$min,$hour,$mday,$mon,$year,$wday,$yday,$isdst) = 
localtime(time);
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and

$mday is the day of the month and $mon the month in the range 0..11, with 0 indicating January and 11 indicating December. This makes it easy to get a month name from a list:

  my @abbr = qw(Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec);
  print "$abbr[$mon] $mday";
  # $mon=9, $mday=18 gives "Oct 18"
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$year contains the number of years since 1900. To get a 4-digit year write:

  $year += 1900;
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Given this, then:

# 2014-02
perl -le 'my (@ym) = (localtime($^T))[5,4]; $ym[0] += 1900; 
$ym[1]++; print sprintf qq{%4d-%02d}, @ym;'
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or

# 2014-Feb
perl -le 'my @abbr = qw(Jan Feb Mar Apr May Jun Jul Aug Sep 
Oct Nov Dec); my (@ym) = (localtime)[5,4]; 
$ym[0]+= 1900; print sprintf qq{%4d-%3s}, $ym[0], $abbr[$ym[1]];'
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Hope that helps.