tabs in vi

[John Stafford]

BEWARE:  Most versions of vi I've seen can trash your file if you pipe
too much though a filter program (like expand).  I have had files
trashed doing exactly 1G!Gexpand.  You get a block of lines replaced
with blank lines and the original lines get moved someplace else and
rotated to various degrees.

I believe a race condition is involved.  While the failure is rare and
correlates positively with increasing file size, I have never known
exactly what triggers it (I'm sure somebody reading this knows and can
enlighten us).