sort lexicographically and numerically at the same time

Question

I have a file tmp.txt (actually the output of a bash command) with entries like:

    ...
ammp            0                1.03683
ammp            10               2.69954
ammp            1                1.05712
ammp            11               2.70339
ammp            12               2.70339
ammp            2                1.88586
ammp            3                2.50103
ammp            4                2.64734
ammp            5                2.67462
ammp            6                2.68097
ammp            7                2.68631
ammp            8                 2.6904
ammp            9                2.69517
applu           0               0.678798
applu           10              0.922213
applu           1               0.901234
applu           11              0.923596
applu           12              0.923596
applu           2               0.901657
applu           3               0.903176
applu           4               0.908912
applu           5               0.913879
applu           6               0.914885
applu           7               0.915516
applu           8               0.917368
applu           9               0.920753
apsi            0                1.09037
apsi            10               2.20494
apsi            1                1.16651
apsi            11               2.24381
apsi            12               2.24381
apsi            2                1.49532
apsi            3                1.79137
apsi            4                1.79581
apsi            5                1.79601
apsi            6                1.80062
apsi            7                1.91269
apsi            8                 1.9579
apsi            9                2.00872
    ...

I want to sort it according to the first field and then the second. The problem is that I want lexicographical sort for the first field and numerical for the second.

I have tried the following:

cat tmp.txt | sort -k1,2

sorts both fields lexicographically

cat tmp.txt | sort -k1 | sort -n -k2

the second sort messes the first.

cat tmp.txt | sort -s -k1.2n

supposedly stable sort that does the second field numerically. Does not work, and sorts second field lexicographically...

Ideas??

Answer 1

Try:

sort -k 1,1 -k 2,2n file

This will sort on the first field alphabetically and then on the second field numerically.

The sort man page has some examples.