Bash sort Command - Sort Lines of Text Files

Using the sort Command

The sort command is used to sort lines of text files.

It's a handy tool for organizing data in files.

Basic Usage

All examples on this page use this fruits.txt file:

bananas,2
apples,1
kiwis,3
oranges,20
bananas,4
kiwis,3

To sort a file, use sort filename:

sort fruits.txt
apples,1
bananas,2
bananas,4
kiwis,3
kiwis,3
oranges,20

Options

The sort command has options to change how it works:

• -r - Sort in reverse order
• -n - Sort numbers correctly
• -k - Sort by a specific column
• -u - Remove duplicate lines
• -t - Specify a delimiter for fields

Sort in Reverse Order

The -r option allows you to sort in reverse order.

Without this option, sort arranges lines in ascending order.

sort -r fruits.txt
oranges,20
kiwis,3
kiwis,3
bananas,4
bananas,2
apples,1

Specify a Delimiter for Fields

The -t option specifies a delimiter for fields, which is useful for sorting files with a specific field separator.

Without this option, sort assumes whitespace as the default delimiter.

sort -t "," -k2,2 fruits.txt
apples,1
bananas,2
oranges,20
kiwis,3
kiwis,3
bananas,4

This example also uses -k to sort by the second column.

Sort by a Specific Column

The -k option allows you to sort by a specific column.

Without this option, sort uses the entire line as the key.

You can add letters like n (numbers) and r (reverse) to the key itself. Here, -k2,2nr sorts the second column as numbers, largest first:

sort -t "," -k2,2nr fruits.txt
oranges,20
bananas,4
kiwis,3
kiwis,3
bananas,2
apples,1

Sort Numbers Correctly

The -n option allows you to sort numbers correctly.

Without this option, numbers are sorted lexicographically, meaning "10" would come before "2".

sort -t "," -n -k2,2 fruits.txt
apples,1
bananas,2
kiwis,3
kiwis,3
bananas,4
oranges,20

Remove Duplicate Lines

The -u option removes duplicate lines from the output. Without this option, duplicate lines are retained.

sort -u fruits.txt
apples,1
bananas,2
bananas,4
kiwis,3
oranges,20

Complex Sorting

Sort can perform complex sorting tasks. For example, sort -t "," -k1,1 -k2,2r fruits.txt sorts by the first column, and then by the second column in reverse order.

sort -t "," -k1,1 -k2,2r fruits.txt
apples,1
bananas,4
bananas,2
kiwis,3
kiwis,3
oranges,20