Re: Sponge [was: Delete all after a pattern]

[Lee <ler762@gmail.com>]

On 9/3/19, Greg Wooledge <wooledg@eeg.ccf.org> wrote:
> On Sat, Aug 31, 2019 at 06:28:15PM +0200, tomas@tuxteam.de wrote:
>> Me too, I didn't know about sponge. Small, nifty utility, doing one
>> thing -- pretty Unixy.
>
> Oh god, no.  Don't use sponge unless you enjoy data loss.

Nope - don't enjoy data loss at all.

> See <https://mywiki.wooledge.org/BashPitfalls#pf13>.

Just out of curiosity,
  sed 's/foo/bar/g' file > tmpfile && sync && mv tmpfile file
seems to be the 'more correct' version of
  sed 's/foo/bar/g' file > tmpfile && mv tmpfile file

Do you ever take it that far or is the "slight risk of data loss in
case of a system crash / power loss" so slight that you don't bother?


for whatever it's worth, if I was looking at the line
  sed 's/foo/bar/g' file > tmpfile && mv tmpfile file
and trying to come up with all the ways it could fail, I'd change it to
  /bin/sed 's/foo/bar/g' file > tmpfile && /bin/mv tmpfile file
so this wouldn't happen
$ sed  -e 's/$/\//' file > tmpfile && mv tmpfile file
mv: overwrite 'file'?

but it would have never occurred to me that I needed a sync before the mv

Thanks,
Lee