问重音(`)符号在终端中有什么作用

EN

Command Substitution
       Command substitution allows the output of a command to replace the com-
       mand name.  There are two forms:
          $(command)
   or
          `command`

   Bash performs the expansion by executing command and replacing the com-
   mand substitution with the standard output of  the  command,  with  any
   trailing newlines deleted.  Embedded newlines are not deleted, but they
   may be removed during word splitting.  The command  substitution  $(cat
   file) can be replaced by the equivalent but faster $(< file).