Easier yet with sed and date: 
date -d @$(sed -n '/^btime /s///p' /proc/stat)

[download]
(OK, there's no Perl here, but that was just for the thrill of "improving" upon a Randal L. Schwartz solution :)

In reply to Re^2: linux boot time by nico57
in thread linux boot time by da w00t

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