Add handling for any nil-length string passed to -i for the backup extension.

Add a note that this is kinda-sorta dangerous to the manual page.

1 files changed, 7 insertions, 0 deletions

diff --git a/usr.bin/sed/sed.1 b/usr.bin/sed/sed.1
index 4005463..e7bd8b2 100644
--- a/usr.bin/sed/sed.1
+++ b/usr.bin/sed/sed.1
@@ -102,6 +102,13 @@ The editing commands should each be listed on a separate line.
 .It Fl i Ar extension
 Edit files in-place, saving backups with the specified
 .Ar extension .
+If a zero-length
+.Ar extension
+is given, no backup will be saved.
+It is not recommended to give a zero-length
+.Ar extension
+when in-place editing files, as you risk corruption or partial content
+in situations where disk space is exhausted, etc.
 .It Fl n
 By default, each line of input is echoed to the standard output after
 all of the commands have been applied to it.