seq — Generate number sequences

Linux / Basic Linux commands / seq.html

Prints a sequence of numbers within a range at a given step.

Basic Information

What is this command?

seq takes start, step and end values and prints numbers one per line. It is commonly used to build loop ranges or generate test data.

-w pads numbers to a fixed width and -f applies a printf format. Floating point is supported but precision caveats apply.

What problems does it solve?

• Building loop ranges
• Generating sequentially numbered file names
• Creating numeric test data
• Producing descending or stepped sequences

Key features

Basic sequence

Given start and end, it counts by one.

• When to use: Creating a simple range
• What you get: It plugs directly into loops.
• Limitations: Large ranges produce huge output.

Custom step

The middle argument sets the increment.

• When to use: Even numbers or steps of five
• What you get: Produces exactly the desired sequence.
• Limitations: Floating steps can accumulate rounding error.

Formatting

-w and -f control width and format.

• When to use: Zero-padding file names
• What you get: Names sort correctly.
• Limitations: A malformed format string causes an error.

Installation and usage

Check whether it is installed

seq --version

sudo apt install coreutils # Debian/Ubuntu sudo dnf install coreutils # Fedora

Real-world examples

One to five

Print a basic sequence.

seq 1 5

Custom step

Count from 0 to 10 by two.

seq 0 2 10

Zero padding

Produce 01 through 05.

seq -w 1 5