Shell Programming and Scripting

date +"%Y%m%d%H"

date +"%Y%m%d%H" -d"-1hour"
2017052809

date +"%Y%m%d%H" -d"-1hour"

hour()
{
    perl -e '
    use POSIX qw(strftime);
    my $now = time - 3600;   # one hour is 3600 seconds
    my $now_string = strftime "%Y%m%d%H", localtime($now);
    print $now_string, "\n";
    '
}

#usage:
datestr=$( hour )
echo $datestr

perl -MPOSIX -le 'print strftime "%Y%m%d%H", localtime(time - 3600)'