fold Command in Linux
The Linux fold command wraps each input line to fit the specified width. It takes the text and breaks it into chunks to make it more readable in the terminal.
The fold command makes the files with long lines more comprehensible on a terminal with limited width. By default, it wraps lines by 80 columns. However, it can be modified.
Table of Contents
Here is a comprehensive guide to the options available with the fold command −
Syntax of fold Command
The syntax of the Linux fold command is as follows −
fold [options] [file]
The [options] field in the above command is used to specify options to modify the behavior of the command. The [file] field is used to specify the file that needs to be printed in the standard output.
Options of fold Command
The options of the fold command are listed below −
| Flags | Options | Description |
|---|---|---|
| -b | --bytes | It is used to set width by bytes rather than columns |
| -c | --characters | It is used to set width by characters instead of columns |
| -s | --spaces | It is used to break the line in spaces |
| -w width | --width=width | It used to specify a custom width instead of the default 80 |
| --help | It is used to display command help | |
| --version | It is used to display the command version |
Examples of fold Command in Linux
This section demonstrates the usage of the fold command in Linux with examples −
Wrapping Lines
To wrap lines of a text file with long lines by 80 columns, use the fold command with the file name.
fold file.txt
Wrapping Lines with Custom Width
By default, the fold command wraps lines by 80 columns. To change the default value, use the -w or --width options −
fold -w 50 file.txt fold --width=50 file.txt
Breaking Lines in Spaces
By default, the fold command breaks the lines in the middle of the word. However, to prevent this behavior, use the -s or --spaces options −
fold -s -w 50 file.txt fold --spaces --width=50 file.txt
Making the Format Permanent
To make the modified format of the lines permanent, redirect the standard output to another file.
fold -w 50 file.txt > newfile.txt fold --width=50 file.txt > newfile.txt
Wrapping Lines of Standard Input
To wrap a long line of standard input, use the fold command in the following way −
echo "Linux is a versatile and open-source operating system widely used in various industries, from personal computing to enterprise servers" | fold -s -w 40
Reading Log with the fold Command
The log can be tough to read in the terminal. To make them readable, the fold command can be a handy tool.
sudo journalctl | fold -s -w 50
Conclusion
The fold command in Linux is used to wrap long lines to make them more readable on a screen with limited width. By default, it wraps each line by 80 columns. However, it can be changed. If the text file is not specified then the standard input is wrapped.
In this tutorial, we explained the fold command, its syntax, options, and usage in Linux through examples.