Re: sed -i should require write access (was: Bug in sed)

[Bob Proulx]

Paul Eggert wrote:
> Bob Proulx wrote:
> > That is the way Unix filesystem permissions work.
> 
> Yes, but still, it's bogus that "sed -i" overwrites a
> read-only file.  That's not what users expect, and it's
> not what the documentation says.  The documentation
> says that -i "overwrites the file in place", which implies
> that you must have write access to the file.

Changing this behavior would make sed incompatible with perl.  I think
in this case since perl is the grandfather of this functionality that
keeping in close sync with perl is important.  It drives what is
expected behavior.

  echo "hello world" > file
  chmod a=r file
  perl -pi -e s/hello/my/ file

Also changing this after all of this time would almost certainly come
as a surprise to people who are using the current behavior.  Suddenly
scripts that have been working successfully to edit files will stop
working.  That is going to greatly irritate them.

> How about the following patch, to fix this?

Note that I didn't look at the patch itself.

Bob