Master Linux fmt: Format Text, Adjust Width, Highlight Lines & More

Overview

The fmt command is a convenient text‑formatting tool that makes your text look tidy by adjusting line width and paragraph layout. It can process file contents or read from standard input, producing neatly formatted output.

Default Behavior

By default, fmt sets each line to 75 characters, but you can change this width with command‑line options, making it a practical utility for quickly standardizing text layout.

Basic Syntax

The basic usage of fmt follows this pattern: fmt [-WIDTH] [OPTION]... [FILE]... The command reformats each paragraph in the input file(s) and writes the result to standard output. Use the -WIDTH option to specify a different line width.

Common Q&A Examples

Q1: How to format a file into a single line?

Run fmt with the file name as the argument: fmt filename This merges the file’s multiple lines into one line of output without modifying the original file.

Q2: How to change the maximum line width?

Use the -w option followed by the desired width: fmt -w 20 filename For example, setting the width to 20 characters.

Q3: How to highlight the first line?

Apply the -t option to give the first line a different indentation, making it stand out.

fmt -t filename

Q4: How to split overly long lines?

Use the -s option to break long lines into shorter ones:

fmt -s filename

Q5: How to set spacing between words and sentences?

The -u option ensures one space between words and two spaces between sentences; this option is enabled by default.

fmt -u filename

Conclusion

Although fmt offers simple functionality, it remains a powerful tool for text formatting tasks such as adjusting line width and maintaining consistent layout, making it valuable for quick text adjustments in Linux environments.