O LC_NUMERIC
locale determina o caractere de ponto decimal.
LC_ALL=C sort -g output.out > sorted.out
Exemplo
$ echo "$LC_ALL"
de_DE
$ sort -g foo
0.100159E+00 0.998410E+01 121.0000
0.100753E+00 0.992529E+01 126.8500
0.101409E+01 0.986102E+00 130.8000
0.102260E-01 0.977901E+02 123.4000
0.102844E+00 0.972347E+01 120.9500
0.107397E-02 0.931122E+03 124.0500
$ LC_ALL=C sort -g foo
0.107397E-02 0.931122E+03 124.0500
0.102260E-01 0.977901E+02 123.4000
0.100159E+00 0.998410E+01 121.0000
0.100753E+00 0.992529E+01 126.8500
0.102844E+00 0.972347E+01 120.9500
0.101409E+01 0.986102E+00 130.8000