sort — Linux basic command

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A command for sorting lines in text files. Supports deduplication, numeric sorting, reverse order, and more.

Basic Information

What is this command?

sort is a command for sorting lines in text files. It offers various sorting options such as lexicographic, numeric, reverse, and deduplication, and is often used to sort the output of other commands via pipes.

It includes features useful for data processing, such as sorting by specific columns with the -k option and specifying delimiters with the -t option.

What problem does it solve?

• Sorts file contents in lexicographic order.
• Sorts logs in chronological or reverse order.
• Removes duplicate lines.
• Sorts data based on a specific column.

Key Features

Default Sorting

Sorts lines in lexicographic (ASCII) order.

• Use Case: When organizing lists like names alphabetically.
• Result: The sorted output is displayed.
• Limitation: It may be case-sensitive (LC_ALL=C).

Numeric Sorting (-n)

Sorts by recognizing numeric values.

• Use Case: When sorting numeric data like sizes or scores.
• Result: 10 comes after 9.
• Limitation: Non-numeric values are treated as 0.

Reverse Sorting (-r)

Outputs the sorted results in reverse order.

• Use Case: When you want to see the largest values first.
• Result: Descending order results are displayed.
• Limitation: Used in conjunction with other sorting options.

Deduplication (-u)

Removes duplicate lines.

• Use Case: When eliminating duplicate entries from a list.
• Result: Only unique lines remain.
• Limitation: Duplicate detection occurs after sorting.

Installation and Execution

Verify Pre-installation

It is included by default in all Linux distributions.

which sort
sort --version

Separate Installation (Lightweight Environments)

It is generally already installed.

sudo apt install coreutils   # Debian/Ubuntu

Practical Usage Examples

Basic Sorting

Sorts a file in lexicographic order.

# Sort a file
touch names.txt
echo -e "Charlie\nAlice\nBob" > names.txt
sort names.txt

# Output:
# Alice
# Bob
# Charlie

# Reverse order
sort -r names.txt

Numeric Sorting

Sorts numeric data.

# Sort numbers
touch numbers.txt
echo -e "10\n2\n1\n20" > numbers.txt
sort -n numbers.txt

# Output:
# 1
# 2
# 10
# 20

# Reverse order (largest number first)
sort -rn numbers.txt

Specific Column and Deduplication

Sorts by a specific column and removes duplicates.

# Sort a CSV file by the 2nd column
cut -d',' -f2 data.csv | sort

# Deduplicate
cat names.txt | sort -u

# Count lines after deduplication
sort names.txt | uniq | wc -l

# Sort logs by time
cat access.log | sort -k4