#!/bin/bash# script "set-test"# Invoke this script with three command line parameters,# for example, "./set-test one two three".echoecho "Positional parameters before  set \`uname -a\` :"echo "Command-line argument #1 = $1"echo "Command-line argument #2 = $2"echo "Command-line argument #3 = $3"set `uname -a` # Sets the positional parameters to the output               # of the command `uname -a`echo $_        # unknown# Flags set in script.echo "Positional parameters after  set \`uname -a\` :"# $1, $2, $3, etc. reinitialized to result of `uname -a`echo "Field #1 of 'uname -a' = $1"echo "Field #2 of 'uname -a' = $2"echo "Field #3 of 'uname -a' = $3"echo ---echo $_        # ---echoexit 0