Sort text numberically with Linux sort

Problem:

Sort the following items in input.txt by the number in them.

a_100
b_101
c_102
d_23
e_24
f_25

Expected output:

d_23
e_24
f_25
a_100
b_101
c_102

Solution: sort -t '_' -k 2n input.txt

Explanation:

• -t '_': set the delimiter to the underscore character
• -k 2n: sorts by the second column using numeric ordering

Reference: http://stackoverflow.com/questions/13088370/sort-numerically