foldcommand in Linux is used to wrap the input text to fit a specified width.
This is particularly useful when dealing with long lines of text that extend beyond the viewable area of a terminal or when formatting text to be sent to devices with a fixed width, like printers.
The basic syntax of the
fold command is as follows:
fold [OPTIONS]... [FILE]...
When no FILE, or when FILE is -, the command reads standard input.
Below is a table summarizing the most common options available with
|Wrap lines at WIDTH columns (default is 80).
|Count bytes rather than columns (ignores line spacing).
|Break at spaces (wraps lines at word boundaries).
Creating a Sample Text File with
To create a sample file to work with the
fold command, we can use
the terminal and type:
i to enter insert mode and copy or type the following long line of text:
This is a very long line of text that is meant to be an example to demonstrate how the fold command works in a Linux environment. By using fold, we can adjust the width of the text so that it wraps and fits nicely into a specified width.
To save and exit
:wq, and hit
Examples of Using
Example 1: Basic Wrapping
To wrap the text at the default width (80 columns):
This will output the text with each line wrapped at 80 columns.
Example 2: Custom Width
To wrap lines to a width of 40 columns:
fold -w 40 longtext.txt
This changes the wrap width to 40 columns.
Example 3: Wrap at Word Boundaries
To avoid breaking words, use the
fold -s -w 40 longtext.txt
This wraps lines at the last space before the 40-column width.
Example 4: Counting Bytes Instead of Columns
If you're dealing with a file where you need to count bytes rather than columns (maybe because of multibyte characters), use:
fold -b -w 40 longtext.txt
This will count bytes, ensuring that multibyte characters are not split.
fold with Other Commands
fold can be used in combination with other Unix commands through piping. For
example, to view the wrapped content with
fold -w 40 longtext.txt | less
Or to save the wrapped version to a new file:
fold -w 40 longtext.txt > wrappedtext.txt
fold command is an essential text processing tool in Unix-like operating
systems for ensuring that output fits within a certain width. It's especially
handy for formatting text on the command line, scripting, and preparing data for
display on devices with strict width constraints.
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