Sorting a data file

[Ibrahim F Haddad]

Hello all,

Given a file that contains data of the following format:

7.606565 5.404950
4.969272 4.597600
4.969272 4.597600
2.400000 3.486746
3.000000 3.672252
3.600000 3.766663


How to sort it in increasing order of the x column so
after sorting it looks like that:

2.400000 3.486746
3.000000 3.672252
3.600000 3.766663
4.969272 4.597600
4.969272 4.597600
7.606565 5.404950

please note that duplicate entries may exist.

Thank you very much.

-ibrahim