# on old Linux distros CentOS 6.0 etc. with dmesg (part of util-linux-ng-2.17.2-12.28.el6_9.2.x86_64) etc. dmesg -T not available
# workaround is little pl script below
dmesg_with_human_timestamps () {
    $(type -P dmesg) "$@" | perl -w -e 'use strict;
        my ($uptime) = do { local @ARGV="/proc/uptime";<>}; ($uptime) = ($uptime =~ /^(\d+)\./);
        foreach my $line (<>) {
            printf( ($line=~/^\[\s*(\d+)\.\d+\](.+)/) ? ( "[%s]%s\n", scalar localtime(time - $uptime + $1), $2 ) : $line )
        }'
}
alias dmesg=dmesg_with_human_timestamps