Xargs

xargs is a powerful GNU utility that transforms piped data into arguments for another command. Instead of reading from stdin and writing to stdout like typical pipelines, xargs gathers items and appends them as parameters—enabling more flexible shell scripting and one-liners.

Table of Contents

1. Piping Basics
2. How xargs Works
3. Common Use Cases
4. Handling Special Characters
5. Additional Resources

Piping Basics

Most shell utilities can read from stdin or files. For example, to count words:

echo "How many words are in this text?" | wc -w
# 7

You can redirect or pipe interchangeably:

sort file.txt
sort < file.txt

cat file.txt
cat < file.txt

By contrast, xargs acts like a “bucket”—it collects output from a previous command and then invokes another command, passing those collected items as arguments.

How xargs Works

Assume file.txt contains:

file
content
to demonstrate
xargs functionality

Piping to echo without xargs preserves newlines in the input stream but not in output:

cat file.txt | xargs echo
# file content to demonstrate xargs functionality

Under the hood, xargs:

1. Reads whitespace (spaces, tabs, newlines) by default.
2. Constructs a single command line by concatenating all items.
3. Executes that command:

echo file content to demonstrate xargs functionality

Common Use Cases

Supplying Arguments to Commands

Commands like rm, ls, mkdir or even custom scripts require positional arguments. Instead of writing loops, xargs can automate this:

# Prepend a custom message to file.txt contents
cat file.txt \
  | xargs echo "The contents of file.txt passed by xargs are:"
# The contents of file.txt passed by xargs are: file content to demonstrate xargs functionality

Creating Multiple Directories

Generate directories from a whitespace-separated list:

echo "dir1 dir2 dir3" \
  | xargs mkdir
ls
# dir1  dir2  dir3

Table of Handy xargs Examples

Handling Special Characters

Additional Resources

• GNU xargs Manual
• Bash Guide: Process Substitution & xargs
• Linux find + xargs Examples