This following command prints nothing on my machine

echo `python3.8 -c 'print ("*"*10)'`

whereas

python3.8 -c 'print ("*"*10)' 

does. Why?

CodePudding user response：

The first example does command substitution for the argument to echo and is equivalent to the command echo **********. This happens to output a list of directory contents, since ********** seems to be equivalent to *¹ and is expanded by the shell.

If you want to prevent the shell to expand **********, you need to quote it:

echo "`python3.8 -c 'print ("*"*10)'`"

which is equivalent to echo "**********".

¹_{don't quote me on that (pun intended)}

CodePudding user response：

`expr` means to evaluate the contents between ' as a command and replace it with the result.

`print(*)` is equal to ` * ` which is evaluated as all the files in the current directory

The output really depends on the machine used