Command usage with options

xargs --version

Prints the version number of xargs command and then exit.

Output :

xargs (GNU findutils) 4.7.0-git
Copyright (C) 2016 Free Software Foundation, Inc.
License GPLv3+: GNU GPL version 3 or later .
This is free software: you are free to change and redistribute it.
There is NO WARRANTY, to the extent permitted by law.

xargs -a test.txt

It will show contents of file

file1
file2
file3
file4

xargs -p  -a test.txt

-p option prompts for confirmation before running each command line. It only runs the command line if the response starts with ‘y’ or ‘Y’ Output :

# xargs -p  -a test.txt
echo file1 file2 file3 file4 ?...y
file1 file2 file3 file4

# xargs -p  -a test.txt                                                                                                                 
echo file1 file2 file3 file4 ?...n

 xargs -r -a test.txt

Now, let’s suppose the file “test.txt” is empty, and above command is executed, -r option ensures if standard input is empty, then command is not executed, so above command will not produce any output, But, if above command is executed without -r option, it will produce a blank line as output. See below image as instance :

xargs is a Unix command which can be used to build and execute commands from standard input.

Importance:

Some commands like grep can accept input as parameters, but some commands accept arguments, this is a place where xargs came into the picture.