Just playing
 

Although I've been using Linux for a while (in various forms - such as Slackware and Cygwin), I never got around to learning the likes of grep, sed and awk. That's what I've been doing over the past few days and today I noticed something with sed. I type the following:


Naturally, it replaces 'world' with 'hull' and prints the result out on the screen. However, when I try overwriting what's in the file by doing this:


it just wipes the file. What do I have to do to overwrite the contents of a file?

Redirect the output to another file (preferably one that doesn't exist), delete the original file, and move (or copy) the new file back in its place.

> file
truncates (sets the file pointer to the start of an empty file) a file.
It happens before grep runs. Grumpy gave you the workaround.

use sed -i
(edit in-place)