20.Sorting_File_Content.md

Sorting File Content

We can sort data in a file using the sort command:

sort filename

This sorts the content based on alphabetical order.

Example:

akshay@Ubuntu:~/Desktopcat a.txt
Sunny  
Bunny  
Chinny  
Pinny  
Vinny  

akshay@Ubuntu:~/Desktopsort a.txt  
Bunny  
Chinny  
Pinny  
Sunny  
Vinny

• To save the sorted content into another file (sorted.txt), use:

sort a.txt > sorted.txt

To sort the content in reverse alphabetical order, use the -r option:

sort -r a.txt > sorted.txt

Removing Duplicate Lines:

To remove duplicate lines from a file, use:

sort -u a.txt | tac > sorted.txt
sort -ru a.txt > sorted.txt

Sorting File Alphabetically:

sort a.txt  
Bunny  
Chinny  
Pinny  
Sunny  
Vinny

Sorting in Reverse Alphabetical Order:

sort -r a.txt  
Vinny  
Sunny  
Pinny  
Chinny  
Bunny

Sorting Alphanumeric Data:

cat a.txt
7  
Sunny  
8  
Bunny  
1  
Chinny  
6  
Vinny  
5  
Pinny  

sort a.txt
1  
5  
6  
7  
8  
Bunny  
Chinny  
Pinny  
Sunny  
Vinny

Sorting Alphanumeric Data in Reverse Order:

sort -r a.txt  
Vinny  
Sunny  
Pinny  
Chinny  
Bunny  
8  
7  
6  
5  
1

Sorting Numeric Data:

By default, the sort command does not sort numbers numerically but based on their string (digit-wise) representation.

cat a.txt  
11  
2  
7  
2222222  
9  

sort a.txt  
11  
2  
2222222  
7  
9

Sorting Numbers Numerically Using the -n Option:

sort -n a.txt  
2  
7  
9  
11  
2222222

Sorting with Unique Lines:

By default, sort includes all lines, including duplicates. Use the -u option to display only unique lines:

cat a.txt  
1  
1  
2  
2  
Sunny  
Sunny  
Bunny  

sort -u a.txt  
1  
2  
Bunny  
Sunny

Commands for Sorting Tabular Data

1. Sort Based on File Size (Ascending Order):

   ls -l /etc | head -10 | sort -k 5n

   This command sorts based on the 5th column (file size) in ascending order.

2. Sort Based on Month:

   ls -l /etc | head -10 | sort -k 6M

   This sorts by the 6th column (month) in ascending order.

3. Sort Based on Number of Links (Descending Order):

   ls -l /etc | head -10 | sort -k 2nr

   Sorts based on the 2nd column (number of links) in descending order.

Sorting Tabular Data Using the -k Option:

The -k option is used to sort based on a specific column.

Example:

ls -l /etc | head -10 | sort -k 5n

This sorts based on file size (5th column) in ascending order.

Sorting Based on Number of Links in Descending Order:

ls -l /etc | head -10 | sort -k 2nr

Finding Lowest and Highest Salaries Using sort:

emp.txt file content:

800: Avinash:500:Warangal  
100: Yashwant:1000:Mumbai  
200: Omkar:2000:Chennai  
300: Chinmay:3000:Hyderabad  
600: Shreya:6000:Hyderabad  
400: Vaibhav:4000:Delhi  
500: Pragati:5000:Hyderabad  
700: Shailesh:7000:Ranchi

1. Find Lowest Salary Record:

   sort -k 3n -t ":" emp.txt | head -1

   This finds the employee with the lowest salary.

2. Find Highest Salary Record:

   sort -k 3nr -t ":" emp.txt | head -1

   This finds the employee with the highest salary.

Working with Unique Content Using uniq

The uniq command is used to display unique lines. However, the file needs to be sorted for uniq to work properly.

Example (Without Sorting):

cat a.txt  
Sunny  
sunny  
Bunny  
Chinny  
Sunny  
Bunny  
Chinny  

uniq a.txt  
Sunny  
sunny  
Bunny  
Chinny  
Sunny  
Bunny  
Chinny

Without sorting, uniq doesn't remove duplicates correctly.

Correct Usage (With Sorting):

sort a.txt | uniq  
Bunny  
Chinny  
sunny  
Sunny

uniq Command Options:

1. To Display Only Duplicate Lines:

   sort a.txt | uniq -d  
   Bunny  
   Chinny  
   Sunny

2. To Display the Number of Occurrences of Each Line:

   sort a.txt | uniq -c  
     2 Bunny  
     2 Chinny  
     1 sunny  
     2 Sunny

3. To Ignore Case While Comparing:

   sort a.txt | uniq -i  
   Bunny  
   Chinny  
   sunny  
   Sunny

4. To Display Only Unique Lines (Lines Not Duplicated):

   sort a.txt | uniq -u  
   sunny