Also risking another RTFM answer, Date::Manip tends to my toolbox of choice for date manipulation. I tried the following with no problems:

use Date::Manip;
#use warnings; # Skipped for quick example
#use strict; # Skipped for quick example
Date::Manip::Date_Init('TZ=US/Mountain');

print johannz('yesterday');

sub johannz {
    return Delta_Format(DateCalc('today',shift()), 0, '%sv s:%mv m:%hv
+ h - %dv d/%Mv M/%yv y');
}
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I like Date::Manip because it accepts such a wide variety of date formats. It's a DWIM module in that regard.