Intro
From the man page of xargs:
The xargs utility reads space, tab, newline and end-of-file delimited strings from the standard input and executes utility with the strings as arguments.
Useful when used with tools that can't read piped content by themselves, eg. ls.
Robins-MacBook-Pro-2:/ robin$ echo /opt | ls
Applications System cfg dev lost+found private tmp
Benutzerinformationen Users collectionCache.bnk docs mach_kernel sbin usr
Library Volumes cores etc net share var
Network bin data home opt tests www
Robins-MacBook-Pro-2:/ robin$
Robins-MacBook-Pro-2:/ robin$ echo /opt | xargs ls
X11
Robins-MacBook-Pro-2:/ robin$
TIL
xargs is capable of invoking the provided utility not once with all the arguments provided, but also invoking the utility e.g. once per argument.
Example utility invoked once with all arguments
Robins-MacBook-Pro-2:/ robin$ echo /opt /dev /Volumes | xargs echo
/opt /dev /Volumes
Robins-MacBook-Pro-2:/ robin$
Example utility invoked once per argument
Robins-MacBook-Pro-2:/ robin$ echo /opt /dev /Volumes | xargs -n1 echo
/opt
/dev
/Volumes
Robins-MacBook-Pro-2:/ robin$
Usecase
I used it to created a lot of copies of the same file at once.
Robins-MacBook-Pro-2:cpfoo robin$ ls
source
Robins-MacBook-Pro-2:cpfoo robin$ echo destination-{1..5} | xargs -n1 cp source
Robins-MacBook-Pro-2:cpfoo robin$ ls
destination-1 destination-2 destination-3 destination-4 destination-5 source
Robins-MacBook-Pro-2:cpfoo robin$
This snippet also makes use of a feature called brace expansion, which I'll probably also cover sometimes.