Introduction

Certain Linux commands take input both from the standard input (stdin) and as a command-line argument. However, others are designed to take input only as an argument. To be able to process the standard input, those Linux commands need to utilize the xargs command.In this tutorial, you will learn how to use the Linux xargs command to manipulate the standard input and work with other commands.
How to Use the Linux xargs Command

Prerequisites

  • A system running Linux
  • Access to the command line

What is the xargs Command?

The xargs command builds and executes commands provided through the standard input. It takes the input and converts it into a command argument for another command. This feature is particularly useful in file management, where xargs is used in combination with rm, cp, mkdir, and other similar commands.

How to Use the xargs Command With Examples

When used on its own, xargs prompts the user to enter a text string that it then passes to the echo command.
The basic function of the xargs command
The example shows an example input, followed by the output of the echo command.
Note: The echo command is a built-in Linux feature that prints out arguments as the standard output. echo is commonly used to display text strings or command results as messages. Learn about all the different ways you can use the echo command in Linux.

Combine xargs with find

The find command often precedes xargs in a pipeline. Use it to provide a list of files for further processing by xargs. The syntax looks like this:
find [location] -name "[search-term]" -type f | xargs [command]
Using the xargs command with the find command in a pipeline
The example above demonstrates using the find command to find all files with the .sh extension. The list of files is then piped to xargs, which uses the rm command to delete them.However, xargs does not automatically include files which contain blank spaces in their names. To include those files too, use the -print0 option for find, and the -0 option for xargs:
find [location] -name "[search-term]" -type f -print0 | xargs -0 [command]
Using the xargs command with the find command in a pipeline, using the -print0 and -0 arguments
rm now deletes all the files with the .sh extension.

Combine xargs with grep

Use xargs with the grep command to search for a string in the list of files provided by the find command.
find . -name '[search-term]' | xargs grep '[string-to-find-in-files]'
Using the grep command with xargs to search files for stings
The example above searched for all the files with the .txt extension and piped them to xargs, which then executed the grep command on them.

Xargs Multiple Commands

To run more than one command with xargs, use the -I option. The syntax is:
[command-providing-input] | xargs -I % sh -c '[command-1] %; [command-2] %'
Running multiple commands with the xargs command
In the example, the contents of file4.txt were displayed first. Then mkdir created a folder for each word in the file.

Read Items From File

As mentioned before, xargs reads the standard input. Use the -a option to read the contents of a file instead.
xargs -a [filename]
Using the -a option to tell xargs to read from a file instead of standard input

Find and Archive Images Using tar

When used with the tar command, xargs creates a tar.gz archive and populates it with files provided by the find command.
find [location] -name "[search-term]" -type f -print0 | xargs -0 tar -cvzf [tar-gz-archive-name]
Using the xargs command to compress files into a tar.gz archive
To see the commands executed by xargs in standard output, use the -t option.
[command-providing-input] | xargs -t [command]
Using the -t option with xargs to see the commands executed by xargs
In the example above, notice that xargs executed the mkdir command on the entire string provided by echo.

Approve xargs Command Execution

Some xargs operations, like removing files and folders, are irreversible. To control the execution of those commands, use the -p option.
[command-providing-input] | xargs -p [command]
Using the -p option with xargs to approve execution of commands
When you execute the command with the -p option, xargs displays a confirmation line before executing it. Type y to proceed, or n to cancel the operation.

Limit Output per Line

Sometimes it is necessary to control the number of arguments xargs takes at the same time. Perform this action using the -n option followed by the number of arguments you are limiting xargs to:
[command-providing-input] | xargs -n [number] [command]
In the example below, xargs takes the string from the echo command and splits it into three. Then it executes another echo for each of the parts:
Using the -n option to limit the number of arguments xargs passes at the same time

Specify the Delimiter

The default xargs delimiter is a blank space. To change the default delimiter, use the -d command followed by a single character or an escape character such as n (a new line).
[command-providing-input] | xargs -d [new-delimiter] | xargs [command]
In the example below, the xargs command instructs the system to use * as a delimiter and apply mkdir to each of the obtained arguments.
Using a custom delimiter with the xargs command

List All Linux User Accounts on the System

Use xargs to organize the output of the commands, such as cut. Consider the following example:
cut -d: -f1 < /etc/passwd | sort | xargs
The cut command accesses the /etc/passwd file and uses the : delimiter to cut the beginning of each line in the file. The output is then piped to sort, which sorts the received strings, and finally to xargs that displays them:
Using xargs to list all Linux user accounts on the system
Note: For alternative ways to list users, read How to List Users in Linux.

Remove Blank Spaces in String

Since xargs ignores blank spaces when looking for arguments, the command is useful for removing unnecessary blank spaces from strings.
echo "[string-with-unnecessary-spaces]" | xargs
Removing unnecessary blank spaces with xargs

List Number of Lines/Words/Characters in Each File

Use xargs with the wc command to display a list of files with the line, word, and character count.
ls | xargs wc
The example below instructed the ls command to pipe to xargs only the files containing the word “example”. xargs then applied wc to that list:
Using the wc command with xargs

Copy File to Multiple Directories

Copy files to multiple directories using the xargs command. The syntax is simple:
echo [directory-1] [directory-2] | xargs -n 1 cp -v [filename]
Using xargs to copy a file to multiple directories
The echo command provides directory names, and xargs uses the cp command to copy the given file into each of the directories.

Conclusion

After completing this tutorial, you should know how to use the xargs command. The article provided a list of command options and showed how to use xargs in combination with the commands that are frequently used with it.