Sort

Basics

• Reverse: sort -r
• Random: sort -R

Sorting by field

We specify field by the -k option.

sort -k2 <file>

but this will do a lex order sort on that field. If we want a numerical sort:

sort -n k2 <file>    # or
sort -g k2 <file>

the first, sort -n sorts integers, the second sorts floats and 1.3e4 too. Consider the input

hello 1 flibble
hello 2 flibble
hello 10 flibble
hello 13 flibble
hello 21 flibble
hello 21.1 flibble
hello 21.2 flibble
hello 22 flibble
hello 2.21e1 flibble
hello 23 flibble

then sort -k2 will output

hello 1 flibble
hello 10 flibble
hello 13 flibble
hello 2 flibble
hello 2.21e1 flibble
hello 21 flibble
hello 21.1 flibble
hello 21.2 flibble
hello 22 flibble
hello 23 flibble

and sort -k2 -n will output (note how 2.21e1 lies between 2 and 10)

hello 1 flibble
hello 2 flibble
hello 2.21e1 flibble
hello 10 flibble
hello 13 flibble
hello 21 flibble
hello 21.1 flibble
hello 21.2 flibble
hello 22 flibble
hello 23 flibble

and sort -k2 -g will output (now 2.21e1 == 22.11 is in the correct place)

hello 1 flibble
hello 2 flibble
hello 10 flibble
hello 13 flibble
hello 21 flibble
hello 21.1 flibble
hello 21.2 flibble
hello 22 flibble
hello 2.21e1 flibble
hello 23 flibble