I mixed up dd's "of" and "if" args once when trying to image a disk. And of course, it failed somewhere in the middle after borking something important.
How to delete all your files
21–30 of 66 posts
Re: How to delete all your files
#22There's a lot of operations from the command line that are too easy to screw up. As much as I love having the power available and I'd certainly not give it up, I can't deny that GUIs (or even just TUIs) are much safer since you can visually validate the selection you've made and there's nothing to make a typo on. They also tend to ask for confirmation on destructive actions or provide an undo mechanism.
Maybe we need transactional file systems. At work, on our databases, when I'm running an ad-hoc update or delete on something that's not trivial to recover then in my DB tool I will often have something like:
BEGIN TRANSACTION
UPDATE ...
SELECT ...
-- COMMIT TRANSACTION
Re: How to delete all your files
#23I mixed up dd's "of" and "if" args once when trying to image a disk. And of course, it failed somewhere in the middle after borking something important.
> At one point, Linus had implemented device files in /dev, and wanted to dial up the university computer and debug his terminal emulation code again. So he starts his terminal emulator program and tells it to use /dev/hda. That should have been /dev/ttyS1. Oops. Now his master boot record started with "ATDT" and the university modem pool phone number. I think he implemented permission checking the following day.
From https://liw.fi/linux-anecdotes/
But if and of are "easy", since they stand for "input file" and "output file"?
Re: How to delete all your files
#24You almost never need to use "*". Use ".", or go up a dir and type the name of the dir.
Yes thanks. I thought running rsync with a "*" looked odd, but didn't completely understand why until now.
Re: How to delete all your files
#25I mixed up dd's "of" and "if" args once when trying to image a disk. And of course, it failed somewhere in the middle after borking something important.
> At one point, Linus had implemented device files in /dev, and wanted to dial up the university computer and debug his terminal emulation code again. So he starts his terminal emulator program and tells it to use /dev/hda. That should have been /dev/ttyS1. Oops. Now his master boot record started with "ATDT" and the university modem pool phone number. I think he implemented permission checking the following day. Fro…
>But if and of are "easy", since they stand for "input file" and "output file"?
Yes, but which hard drive device is which isn't as straightforward. My fault, of course...just got them mixed up.
Re: How to delete all your files
#26I mixed up dd's "of" and "if" args once when trying to image a disk. And of course, it failed somewhere in the middle after borking something important.
dd is one of the most dangerous ones I was thinking of. I hadn't even thought of swapping if and of though, just mistyping the target drive. I would feel so much safer choosing from a list of the drives shown with good identifying info like their manufacturer, size, serial number, and known partitions.
Re: How to delete all your files
#27It's a shame that 'glob is a generator' did not become the standard way of doing things. It would save so much headache (and make writing programs easier) if command * (or similar syntax) expanded to something like command /some/fd where calls to read(/some/fd) produced "expansion_one␀expansion_two␀expansion_three␀...␀" Though exactly how one would plumb this is its own question.
This is possible if you use "xargs" (which runs a command multiple times with different subsets of the arguments), although it is most useful if commands are aware of null-separation (e.g. old-style "find ... -print0 | xargs -0", before "find" added the "+" option).
Re: How to delete all your files
#28I once saw a friend nearly delete all their files using tip#3 from the thread: > never use only * as a wildcard. A ./* would save you in most cases My friend typod that for /* in an rm -rf command but caught it just in time. They seemed like unnecessary characters to me if it does the same as *, and I don't think they do it anymore, but now I'm not sure which is worse... I suppose good backups just go a long way what…
I just did that last weekend! After an allnighter, which isn't easy for me anymore, I typed: ``rm -rf. /*`` with the dot and the space reversed. When the shell threw an error in my face, I thought, "oh, an extra dot." so I deleted the dot and re-run the command. And there goes my configs and most of the dotfiles in my home dir. Luckily, I have backup for some of those, so it wasn't a complete disaster. I don't trust…
This has nothing to do with the OP, but I always rehearse my deletions with "ls -d", and after seeing the output hit the up arrow in my command history and replace it with the rm command I wanted to attempt. I also never use -r without intention - a lot of people use it habitually even when not deleting a directory. Lastly, I never -f, I just chmod first.
Re: How to delete all your files
#29“Because the share contains a file named exactly "--delete", and since it gets sorted first, rsync thinks it to be an argument and deletes everything.” Also because Unix made the mistake (edit: calling this a mistake may be unfair) of having the shell expand wildcards. If it had provided a library for doing that, the “rsync thinks it to be an argument” part wouldn’t happen. Alternatively, a file system could sort hyp…
Right, DOS expects wildcards to be handled by programs. Besides avoiding problems from the shell expanding wildcards in problematic ways, this also enables some neat semantics like some tools accepting wildcards in multiple locations either for recursive path mapping or for a purpose similar to regex capture groups. It also substantially reduces (but does not eliminate) the need to be careful when including literal wildcard characters in commands.
The problem is of course that wildcard handling ends up being inconsistent between tools or entirely missing, although in practice this became less common as various Win32 calls related to file operations had internal wildcard handling, so applications got a basic form "for free".
As with many things in computing it's hard to say that either approach is superior to the other. PowerShell carries on the DOS tradition of not expanding wildcards in the shell, but provides a more complete and standardized wildcard implementation as part of the API to improve consistency.
Re: How to delete all your files
#30rsync -r ./ ~/Documents/ Why would I even need to use *, if I wanted all files from a directory?
Because rsync semantics around the trailing slash are a little confusing and unusual, it's pretty common IME for people to intentionally explicitly define paths to the file with rsync, in order to avoid having to look up which way they need to write the target path.