Here strings are similar to Here documents but allows you to do this on one line:
1command <<<"some string"
For example, the following commands do the same thing, count the number of words in a string:
1echo "This is a test" | wc -w 2 3wc -w <<<"This is a test"
You can also pipe the output of commands as a here string:
1ps -fe | wc -l 2 3wc -l <<<$(ps -fe)
See also: Here document