sort command in Linux with examples

Linux sort command is used for sorting file content in a particular order. It supports sorting of files alphabetically (ascending or descending), numerically, in reverse order, etc. We can also remove duplicate lines from the file. In this article, we’ll see different example usages of the Linux sort command.

When using the sort command

1. Lines beginning with numbers or digits appear before lines with alphabets.
2. Lines starting with lowercase letters will appear before lines beginning with the same letter but in uppercase.

Linux Sort command without any arguements

When sort is used without any arguments, it arranges the contents of a text file in alphabetical order. In this example, we are using the text file fruits.txt as shown below.

To sort in alphabetical order run:

# sort fruits.txt

Output

Sort with -r option

If you wish to sort a file in reverse order using sort command, use the -r option. For instance, to reverse the order of the input file in our previous example, execute:

# sort -r fruits.txt

Output

Sort numerically

To sort a file in a numerical order, use the -n attribute. In this example, we have a file digits.txt as shown below

To sort this file numerically from the smallest value to the largest value execute the command

# sort -n digits.txt

Output

You can also use the -nr option to reverse the order of the numerical results, i.e. sort from the largest to the smallest value

To demonstrate this, we will run the command:

# sort -nr digits.txt

Output

Sort with -o option

The -o option allows the user to write the output of the file onto a new file. Using this option is just the same as redirecting the output to another file as shown:

# sort fruits.txt > newfile.txt

To write the output of a file to a new file using -o option use the syntax

# sort -o newfile.txt filename.txt

For example,

# sort sorted_fruits.txt fruits.txt

Output

Sort with -u option

The -u option is used to remove file duplicates in a text file while at the same time sorting text alphabetically.

In this example, we are going to use cars.txt as shown below

As you can see, we have 2 duplicate car models: Toyota and Porsche.

To remove these duplicates and sort alphabetically, run

# sort -u cars.txt

Output

Sort with -k option

The -k option sorts a table according to the column number. For instance, if you have a table with 2 columns, use -k -2n option to sort the second column.

In this example, we have the text file bonus.txt

To sort the second column execute

# sort -k -2n bonus.txt

Output

Sort months with -M option

Use the -M option to sort a file containing months in ascending order i.e { Jan , Feb, … Nov, Dec }

We have a file months.txt as shown below

To sort the months in order execute:

# sort -M months.txt

Check the version of sort command

To check the version od sort command run

$ sort --version

Output

More options in sort command

To acquaint yourself with more commands other than the ones we’ve covered, visit the sort man page

# man sort