mktemp(3). It would be amazingly unlikely, but the former method
could result in a symlink attack. A better solution would use
${TMPDIR}, though.
o Make sed not overwrite old backup files with no warning.
Perl for such things. The key difference to Perl is that a backup extension
*MUST* be specified, because on one hand it isn't recommended to have options
which optionally take a parameter, and on the other hand, it'd be slightly
unpleasent to implement proper handling for that.
The difference between this and the version posted to developers@ is that it
does handle multiple files in argv after the getopt(3) handling "correctly",
in that the inplace editing-specific code has been moved out to a function,
and that function is used beyond the first file in our linked list.
This option has been documented as FreeBSD-specific in the manpage.
Reviewed by: developers@ (got feedback from: des, fanf, sobomax, roberto,
obrien)
MFC after: 1 week
