sort Command Guide

Basic Usage

By default, sort arranges lines alphabetically.

bash

sort file.txt

Common Options

sort Options

-r	Reverse order (descending)
-n	Numeric sort
-h	Human-readable numbers (1K, 2M)
-k N	Sort by field N
-t CHAR	Use CHAR as field delimiter
-u	Remove duplicate lines
-f	Ignore case
-o FILE	Write output to FILE

Sorting Order

bash

# Alphabetical (default)
sort names.txt

# Reverse alphabetical
sort -r names.txt

# Ignore case
sort -f names.txt

Numeric Sorting

bash

# Alphabetical (wrong for numbers)
echo -e "10\n2\n1\n20" | sort
# Output: 1, 10, 2, 20

# Numeric (correct)
echo -e "10\n2\n1\n20" | sort -n
# Output: 1, 2, 10, 20

# Human-readable sizes
du -h | sort -h
# Properly sorts 1K, 2M, 3G

Warning

Without -n, numbers are sorted alphabetically (1, 10, 2, 20). Always use -n for numeric data.

Sorting by Field

Use -k to sort by a specific column.

bash

# Sort by second field
sort -k2 data.txt

# Sort by third field numerically
sort -k3 -n data.txt

# Sort by second field, then by third
sort -k2,2 -k3,3n data.txt

Custom field delimiter

bash

# CSV file (comma-separated)
sort -t',' -k2 data.csv

# Colon-separated (like /etc/passwd)
sort -t':' -k3 -n /etc/passwd

Removing Duplicates

bash

# Remove duplicate lines
sort -u file.txt

# Same as
sort file.txt | uniq

Practical Examples

Sort processes by memory usage

bash

ps aux | sort -k4 -rn | head -10

Find largest files

bash

du -ah | sort -rh | head -10

Sort IP addresses

bash

sort -t'.' -k1,1n -k2,2n -k3,3n -k4,4n ips.txt

Sort log by timestamp

bash

# ISO format dates sort correctly alphabetically
sort access.log

Count occurrences (with uniq)

bash

# Most common words
cat file.txt | tr ' ' '\n' | sort | uniq -c | sort -rn | head -10

Sort and save to same file

bash

sort -o file.txt file.txt

Check if file is sorted

bash

sort -c file.txt
# Returns exit code 0 if sorted, 1 if not

Random shuffle

bash

sort -R file.txt
# Or use shuf
shuf file.txt

Stable Sort

Use -s for stable sorting (preserves original order for equal elements).

bash

sort -s -k1,1 file.txt

Version Sorting

bash

# Sort version numbers correctly
echo -e "1.2\n1.10\n1.1\n2.0" | sort -V
# Output: 1.1, 1.2, 1.10, 2.0

Summary

sort is essential for organizing text data. Key takeaways:

Use sort -n for numeric sorting
Use sort -r for reverse order
Use sort -k N to sort by field N
Use sort -t to set field delimiter
Use sort -u to remove duplicates
Use sort -h for human-readable sizes

Quick Reference

Basic

Options

Fields

Common

Downloadable Image Preview

Basic Usage

Common Options

sort Options

Sorting Order

Numeric Sorting

Sorting by Field

Custom field delimiter

Removing Duplicates

Practical Examples

Sort processes by memory usage

Find largest files

Sort IP addresses

Sort log by timestamp

Count occurrences (with uniq)

Sort and save to same file

Check if file is sorted

Random shuffle

Stable Sort

Version Sorting

Summary

Related Articles

uniq Command Guide

cut Command Guide

wc Command Guide