[bash]глупый вопрос

     A command substitution is replaced by the output generated by the speci-
     fied command, which is run in a subshell.  For $(command) substitutions,
     normal quoting rules are used when command is parsed; however, for the
     `command` form, a `\' followed by any of `$', ``', or `\' is stripped (a
     `\' followed by any other character is unchanged).  As a special case in
     command substitutions, a command of the form <file is interpreted to mean
     substitute the contents of file.  Note that $(< foo) has the same effect
     as $(cat foo), but it is carried out more efficiently because no process
     is started.

     Note: $(command) expressions are currently parsed by finding the matching
     parenthesis, regardless of quoting.  This should be fixed soon.

TEST=`echo \`which \\\`echo $SHELL\\\`\``

TEST=$(echo $(which $(echo $SHELL)))