Construct argument list(s) and invoke a program (POSIX)
xargs [-itx] [-n numargs] [-P n] [-s size]
[program [initial-arguments]]
The xargs utility uses character strings, read from standard input, to construct a command line which it executes. The specified program and initial-arguments are placed at the beginning of the command line, followed by some number of character strings read. This process continues until the end of the file.
The utility executes a given program with initial-arguments one or more times using the parameters read from standard input. The number of strings appended may be limited by the -n option; the size of the command line may be limited by the -s option.
The strings are separated by blanks or newlines, which may be embedded in the strings by prefixing them with \ or enclosing them in quotes ("). To use the quote character as itself, you must prefix it with a \.
The -i option causes the command to be executed for each string read. Instead of the normal process of appending the string to the command buffer, the initial-arguments are scanned, and every occurrence of {} is replaced by the string. If {} doesn't occur in initial-arguments, the string is appended to the command line and executed.
When a program is executed, it inherits standard output and standard error from xargs. Standard input is set to the controlling tty.
Display the files in the current working directory, and all subdirectories, in two columns:
find . -print | xargs -n 2 echo