What is the difference between $(command) and `command` in shell programming?

Question

To store the output of a command as a variable in sh/ksh/bash, you can do either

var=$(command)

or

var=`command`
         


        

Answer 1

They behave the same. The difference is syntactical: it's easier to nest $() than ``:

listing=$(ls -l $(cat filenames.txt))

vs.

listing=`ls -l \`cat filenames.txt\``