Simple file checking script

Shell Programming and Scripting
1

Hi,

I have a really, what I hope is, simple question.

I'm looking for a simple way to see whether a file exists or not and then perform an action based on whether it exists or not. An example of what I tried is as follows:

if [ "ls /etc/init.d/ | grep mysql" = "mysql" ]
  then {
    echo "File mysql exists"
    some_other_commands_might_go_here;
  }
else {
  echo "File mysql does not exist"
  something_else_to_do_goes_here;
}
fi

Thing is, this doesn't work, so is it something to do with my syntax, or am I just being stupid? Or perhaps a bit of both?

Regards,

Paulo

2 
if [ -f '/etc/init.d/mysql' ]; then
   echo 'exists'
else
   echo 'does NOT exist'
fi