Question: How can i check if one variable has this value do something.Example:

```
$price=$_POST['price'];

if ($price!=90 or $price!=104 or $price!=115 or $price!=120)
{
echo 'not true';
}
else
{
echo 'do something';
}

```

So if the post value has one of those four values do something.

Answer: 
Pass each date through the date command turning them into seconds from the
epoch followed by the original string, do the sort, and remove the added seconds:

```
while read date
do    date --date "$date" +"%s $date"
done |
sort -n -k 1,1 |
sed 's/[^ ]* //'

```
If your version of `sort` implements the `-M` option (sort by month) (and OS X `sort` does), you can sort the strings on the three relevant fields:

```
# First, sort on the 4th field numerically (year)
# In the same year, sort on the 3rd field by month
# In the same year and month, sort on the 2nd field numerically (day)
sort -k4,4n -k3,3M -k2,2n dates.txt

```