How to sort a file, based on its numerical values for a field?

Take a peek at the man page for sort...

   -n, --numeric-sort          compare according to string numerical value

So here is an example...

sort -n filename

If you are sorting strings that are mixed text & numbers, for example filenames of rolling logs then sorting with sort -n doesn't work as expected:

$ ls |sort -noutput.log.1output.log.10output.log.11output.log.12output.log.13output.log.14output.log.15output.log.16output.log.17output.log.18output.log.19output.log.2output.log.20output.log.3output.log.4output.log.5output.log.6output.log.7output.log.8output.log.9

In that case option -V does the trick:

$ ls |sort -Voutput.log.1output.log.2output.log.3output.log.4output.log.5output.log.6output.log.7output.log.8output.log.9output.log.10output.log.11output.log.12output.log.13output.log.14output.log.15output.log.16output.log.17output.log.18output.log.19output.log.20

from man page:

   -V, --version-sort          natural sort of (version) numbers within text

Well, most other answers here refer to

sort -n

However, I'm not sure this works for negative numbers. Here are the results I get with sort version 6.10 on Fedora 9.

Input file:

-0.907928466796875-0.616149902343751.1354064941406250.48614501953125-0.4140167236328125

Output:

-0.41401672363281250.48614501953125-0.61614990234375-0.9079284667968751.135406494140625

Which is obviously not ordered by numeric value.

Then, I guess that a more precise answer would be to use sort -n but only if all the values are positive.

P.S.: Using sort -g returns just the same results for this example

Edit:

Looks like the locale settings affect how the minus sign affects the order (see here). In order to get proper results I just did:

LC_ALL=C sort -n filename.txt