A very dangerous gotcha

[Guest Adriano1]

As I was reading some weeks ago, the result of the command

rm -rf ./.*

is not what one would expect. To see why, feel free to

echo ./.*

 

Especially as root, the consequences could be a bit devastating.

 

Just felt it needed to be said. Please, do feel free to remove this if it's redundant.

[DragonMage]

The command rm -rf can be devastating period. Especially when done as root. There are many horror stories of a sleepy / drunk / stupid administrator accidentally wiped out his hard disk / important files / directories just because of typing this command.

[Guest Adriano1]

yes, but this is especially insidious. What if you want to delete all hidden files on a folder (let's say you wanted to upgrade a system cleanly, for example)? This is the command that comes immediately to mind, yet it would erase all your folders.

[Dyslexic]

I don't get it. I just tried the echo command on my system, and it does exactly what one would think. It returns everything in the current dir that starts with a dot.

[Guest Adriano1]

Hint: look at the first two items in that list. What do you think happens when you do rm -rf ./.. ?

[Dyslexic]

I'd expect to get an error message since bash protects . and ..

[Guest Adriano1]

well, bash is not the only shell out there, as we know. FTR, I saw this gotcha reading through some alt.sysadmin.recovery related pages. Perhaps it doesn't work in some shells. I'll create a new user and test it.

[Havin_it]

Just a small tangential thought, but does rm stop once it has deleted itself?

[Guest Adriano1]

Not necessarily, if it is stored in memory...

[paul]

for i in `find . -type f -name '.*'`
do rm $i
done

 

or

 

find . -type f -name '.*' > filelist
while read filename; do rm "$filename"; done < filelist

 

either of those suggestions should do what you're wanting to do ;)

[Guest Adriano1]

Sure, but they don't immediately come to mind as the quickest option, do they?

 

And also, '.*' doesn't mean "all files that begin with an asterisk or not"? I thougth * here meant "0 or more of the previous".

[Guest Adriano1]

Ok, after a bit of testing I can vouch that at least my bash (FC3) doesn't do evil with my command (outputs "can't delete ." and "can't delete ".."), and also that Paul's first command works.