Newbie question- how do i write a script file to edit another file

[shaggy66]

Hi,
I'm very new to writing script files and I was wondering how I would go about creating a simple script file that would edit another input file. What I have in the input file are geometry locations, but I need to add a negative sign to all the x locations.

"point 0.123 0.456" (a thousand of these "points")

needs to be

"point -0.123 0.456"

There is some other text throughout the file, but this is all i need to do. I'm running a bash shell in fedora.

Thanks

[secondmouse]

Try

awk '/^point/ {print $1,"-"$2,$3}' your_input_file > output_file