copy one file content to another using "sed" editor

Question

I am using shell script. How to copy one file content to another file using "sed". I have to use only sed to complete this copy. can anyone help me?

Thanks in advance Sudha

Answer 1

sed writes its output on standard output, not in a file. You have to use redirections. One possible command is:

sed -n 'p' myInFile > myOutFile

Answer 2

All you need is a noop:

sed -e '' <"${OLDNAME}" >"${NEWNAME}"

...that said, why? Most tiny embedded systems will be using busybox, and while they may not have cp (hey, I've built a busybox without one for a dedicated router appliance!), not adding cat to the busybox config is just silly.

Answer 3

As suggested, you can do this with sed, but why not simply copy the file with the cp command?

Answer 4

If you actually wanted to use the write functionality in sed, you could use the w command to write to a specific file

sed -n "w$NEWNAME" $OLDNAME