column Command — Displaying Text in Tabular Format¶

The column command formats text into neatly aligned columns or tables, making command output much easier to read. It is commonly used to display CSV files, reports, configuration data, and command output in a structured, professional format.

Learning Path¶

Linux Mastery → Module 3: Text Processing → Lesson 12

Difficulty: Beginner → Intermediate

Reading Time: 25 Minutes

Course Progress

Course: Linux Mastery

Module: Text Processing

Lesson: 12 of 18

What You'll Learn¶

After completing this lesson, you'll be able to:

Understand the column command
Format text into aligned columns
Display CSV files as tables
Use custom delimiters
Create professional-looking reports
Format command output
Combine column with other Linux utilities

Prerequisites¶

Before starting this lesson, complete:

Module 1 – Linux Fundamentals
Module 2 – Linux Command Line Essentials
Module 3 Lessons 1–11

Why Learn column?¶

Suppose you have a CSV file.

Alice,Engineering,85000

Bob,HR,60000

Charlie,Finance,90000

David,DevOps,75000

Reading it is possible, but not ideal.

Using:

column -t -s "," employees.csv

Produces:

Alice    Engineering  85000

Bob      HR           60000

Charlie  Finance      90000

David    DevOps       75000

Much easier to read.

What is column?¶

The column command aligns text into multiple columns.

It is mainly used to improve readability.

Syntax:

column [OPTIONS] FILE

Sample File¶

Create:

cat > employees.csv

Contents:

Alice,Engineering,85000

Bob,HR,60000

Charlie,Finance,90000

David,DevOps,75000

Display as Table¶

column -t -s "," employees.csv

Output:

Alice    Engineering  85000

Bob      HR           60000

Charlie  Finance      90000

David    DevOps       75000

Explanation:

-t → Create a table
-s "," → Use comma as the delimiter

Space-Separated Data¶

Create:

server01 Running

server02 Stopped

server03 Running

Display:

column -t servers.txt

Output:

server01   Running

server02   Stopped

server03   Running

Using Colon Delimiters¶

Example:

root:x:0:0

basha:x:1000:1000

Display:

column -t -s ":" passwd.txt

Output:

root   x     0     0

basha  x  1000  1000

Display /etc/passwd¶

column -t -s ":" /etc/passwd

This makes user account information much easier to read.

Format Command Output¶

Disk usage.

df -h | column -t

Processes.

ps -ef | column -t

Mounted filesystems.

mount | column -t

Network connections.

ss -tuln | column -t

Combining with Other Commands¶

Format CSV.

cat employees.csv | column -t -s ","

Display usernames.

cut -d ":" -f1,7 /etc/passwd | column -t -s ":"

Format inventory.

paste servers.txt ips.txt | column -t

Add Headers¶

Create:

Name,Department,Salary

Alice,Engineering,85000

Bob,HR,60000

Display:

column -t -s "," employees.csv

Output:

Name     Department   Salary

Alice    Engineering  85000

Bob      HR           60000

Common column Options¶

Option	Description
`-t`	Create a table
`-s`	Specify delimiter
`-c`	Set output width
`-o`	Set output separator

Change Output Separator¶

Default spacing:

column -t

Custom separator:

column -t -s "," -o " | " employees.csv

Output:

Alice | Engineering | 85000

Bob   | HR          | 60000

Real Production Examples¶

Format Kubernetes output.

kubectl get pods | column -t

Format Docker images.

docker images | column -t

Display Linux users.

column -t -s ":" /etc/passwd

Format inventory.

column -t inventory.csv

Display environment variables.

printenv | column -t -s "="

Production Perspective¶

The column command is useful for:

Reports
CSV files
Server inventories
Configuration reviews
Log summaries
Shell script output

It improves readability without modifying the original data.

Hands-on Lab¶

Task 1¶

Create:

cat > students.csv

Contents:

Rahul,CSE,80

Priya,IT,90

Arjun,ECE,85

Neha,CSE,95

Task 2¶

Display as a table.

column -t -s "," students.csv

Task 3¶

Display /etc/passwd.

column -t -s ":" /etc/passwd

Task 4¶

Format disk usage.

df -h | column -t

Task 5¶

Format environment variables.

printenv | column -t -s "="

Task 6¶

Create an inventory.

Server,Status

server01,Running

server02,Stopped

Display:

column -t -s "," inventory.csv

Task 7¶

Use a custom separator.

column -t -s "," -o " | " students.csv

Task 8¶

Combine with paste.

paste names.txt marks.txt | column -t

Command Deep Dive¶

Command	Purpose	Production Example
`column -t`	Align text	Reports
`column -t -s ","`	Format CSV	Inventory
`column -t -s ":"`	Format passwd	User audit
`column -o " \| "`	Custom separator	Dashboards

Production Troubleshooting Scenario¶

Scenario

A DevOps engineer receives an inventory file.

Server,Status,IP

server01,Running,10.0.0.10

server02,Stopped,10.0.0.11

server03,Running,10.0.0.12

Tasks:

Display it as a table.
Replace commas with aligned columns.
Save formatted output.
Display only the Running servers.

Solutions:

column -t -s "," inventory.csv

column -t -s "," inventory.csv > report.txt

grep Running inventory.csv | column -t -s ","

Mini Challenge¶

Create:

employees.csv

Name,Department,Salary

Alice,Engineering,85000

Bob,HR,60000

Charlie,Finance,90000

David,DevOps,75000

Perform the following:

Display as a table.
Use | as the separator.
Save formatted output.
Display only Engineering employees.
Display only Name and Salary using cut.
Format the result using column.

Best Practices¶

Use column -t for better terminal readability.
Use the correct delimiter with -s.
Format reports before sharing with teammates.
Combine column with cut, paste, and grep.
Remember that column changes only the display, not the original file.

Common Mistakes¶

❌ Forgetting the delimiter.

✅ Incorrect:

column -t employees.csv

Correct:

column -t -s "," employees.csv

❌ Expecting column to modify files.

✅ It only formats the displayed output.

❌ Using column on data with inconsistent delimiters.

✅ Ensure the input is consistently structured.

Interview Questions¶

Beginner¶

What is the purpose of the column command?
What does the -t option do?
How do you display a CSV file as a table?
What does the -s option specify?

Intermediate¶

How do you display /etc/passwd in aligned columns?
Explain the purpose of -o.
How can column improve shell script output?
Why doesn't column modify the original file?

Architect Level¶

How would you generate professional terminal reports from automation scripts?
How can column improve operational dashboards?
How would you combine cut, grep, and column to build an inventory report?

Summary¶

In this lesson, you learned:

Creating aligned tables
Formatting CSV files
Working with custom delimiters
Formatting command output
Combining column with other Linux utilities
Generating professional reports

The column command is a presentation tool that transforms plain text into clean, readable tables. It is especially valuable for displaying reports, inventories, and command output in a format that's easy to understand.

Key Takeaways¶

column formats text into aligned columns.
Use -t to create tables.
Use -s to specify the input delimiter.
Use -o to customize the output separator.
column improves readability without modifying the source data.

What's Next?¶

strings Command — Extracting Printable Text from Binary Files

In the next lesson, you'll learn:

Extracting readable text from binaries
Analyzing executable files
Inspecting libraries and firmware
Malware and forensic analysis basics
Real-world troubleshooting techniques