Remove duplicate xargs item.

Fixes #194.

README.md

@@ -286,12 +286,6 @@ A few examples of piecing together commands:
       find . -type f -ls
 ```
 
-- Use `xargs` or `parallel` whenever you can. Note you can control how many items execute per line (`-L`) as well as parallelism (`-P`). If you're not sure if it'll do the right thing, use xargs echo first. Also, `-I{}` is handy. Examples:
-```sh
-      find . -name '*.py' | xargs grep some_function
-      cat hosts | xargs -I{} ssh root@{} hostname
-```
-
 - Say you have a text file, like a web server log, and a certain value that appears on some lines, such as an `acct_id` parameter that is present in the URL. If you want a tally of how many requests for each `acct_id`:
 ```sh
       cat access.log | egrep -o 'acct_id=[0-9]+' | cut -d= -f2 | sort | uniq -c | sort -rn