How to Sort Data in a File Using Linux

Use the sort command to re-order data in delimited files and from the output of other commands.

This utility is commonly installed by default on major Linux distributions.

Sample Data

The data in a file sorts as long as it is delimited in some way.

For example, take the final league table from the Scottish Premier League for one year and store the data in a file called spl. Create a data file as follows with one club and the data for that club separated by commas on each row.

Team	Goals Scored	Goals Against	Points
Celtic	93	31	86
Aberdeen	62	48	71
Hearts	59	40	65
St Johnstone	58	55	56
Motherwell	47	63	50
Ross County	55	61	48
Inverness	54	48	52
Dundee	53	57	48
Partick	41	50	46
Hamilton	42	63	43
Kilmarnock	41	64	36
Dundee United	45	70	28

How to Sort Data in Files

From that table, you can see that Celtic won the league, and Dundee United came last. If you are a Dundee United fan, you might want to make yourself feel better, and you could do this by sorting on goals scored.

Run the following command:

This time the order would be as follows:

Partick
Kilmarnock
Hamilton
Dundee United
Motherwell
Dundee
Inverness
Ross County
St Johnstone
Hearts
Aberdeen
Celtic

The reason the results are in this order is that column 2 is the goals scored column, and the sort goes from lowest to highest.

The -k switch lets you choose the column to sort by, and the -t switch lets you choose the delimiter.

To make themselves happy, Dundee United fans can sort by column 4 using the following command:

Now Dundee United is at the top, and Celtic is at the bottom.

This would make both Celtic and Dundee fans unhappy. To put things right, sort in reverse order using the following switch:

so

A switch lets you sort randomly, which jumbles up the rows of data.

You can do this using the following command:

so

Case matters! You'll change the order of the sort if you mix up the -r and -R switches.

The sort command can also sort dates into month order. To demonstrate, look at the following table:

Month	Data Used
January	4G
February	3000K
March	6000K
April	100M
May	5000M
June	200K
July	4000K
August	2500K
September	3000K
October	1000K
November	3G
December	2G

The above table represents the month of the year and the amount of data used on a mobile device.

Sort the dates alphabetically using the following command:

sort -k1

Sort by month using the following command:

sort -k1 -t

Looking at the second column, you can see that all the values are in a human-readable format which doesn't look like it would be easy to sort, but the sort command can sort the data-used column by using the following command:

sort -k2 -t

How to Sort Data Passed From Other Commands

The sort command restructures the output from other commands. For example, look at the ls command:

The above command returns each file as a row of data with the following fields displayed in columns:

permissions
node count
username
groupname
size
last access date
file name

Sort the list by file size by running the following command:

To get the results in reverse order, use the following command:

ls

The sort command works in conjunction with the ps command, which lists processes running on your system.

For example, run the following ps command on your system:

The above command returns a lot of information about the processes currently running on your system. One of those columns is the size, and you might want to see which processes are the biggest.

To sort this data by size, use the following command: