Hi, I'm trying to use unix utility ed to search and replace lines in a number of '.id' files

I type the following command:

find -name '*.id' -exec ed {} < ed_script \;

Where the ed_script is the find and replace commands I made.

This ed script only makes the changes to the first file found. If you take away the .id file, then the script will operate on the new file that is first, but it never operates on more than 1 file. Does anyone know why this is? Should I make a more complex script using sed to do my file editing?

Thanks

Hi.

This illustrates one interesting characteristic of processes. Here is my understanding: the script does not directly substitute file ed_script for STDIN for the ed command. Since "< ed_script" is unprotected from the shell, it re-directs for this process, the find process. The child process in which ed runs will inherit this re-direction and can be read once. After that, an EOF is encountered for subsequent reads.

There are a number of solutions. You can place the ed and the re-direct into a second script, omitting any mention of re-direction in the script in which find is located, and calling the new script in the exec portion of the find.

Another solution would be to protect the command ed <ed_script with quotes, but then you would need to use eval to re-scan it. However, a further complication arises because eval is not an external command, it is a shell builtin. That means that you would need to call bash explicitly, like:
One slight drawback to ed is that you will see the character counts for reading and writing when you edit the file.

You don't need to use sed in place of ed, but I tend to use sed. It has an extra complication in that it will require you to use in-place editing in sed, or re-copy the output stream over the source file. I recommend you work on copies of your important files while getting any of these solutions running.

I've tested all of these for this problem (except sed, which is fairly straight-forward).

You could also investigate opening and closing STDIN, but I did not look at that, because you'd probably do that in a script, and. if you're going to write a script, you might as well use the simplest solution.

As an aside, the find command has some interesting features and uses; see http://amitsharma.linuxbloggers.com/how_to_find.htm for an good tutorial with examples.

Best wishes ... cheers, makyo

Yes. sed was designed to operate on streams by default, so you won't have those problems.