sorry - i missed you had written back to this
thread.
I don't know SED very well at all. I would still use grep, but that's just me.
I can't say if your regex is right or not. You originally stated:
These line are starting with empty spaces. So here my requirement is, I need to remove those entire lines from the file using UNIX script.
Your regex will not find lines that start with four spaces, or eleven, or just one.
It will also not find lines that are only blank. It won't find lines like this:
" #ignore this line"
[edit - can't get it to show the leading nine spaces right now...putting in quote to try to force at least one.]
I can't say if your process is right or not, since your specs aren't clear to me.