14.8. Safer File Deletion in Some Directories
Using noclobber (Section 43.6) and read-only files only protects you from a few occasional mistakes. A potentially catastrophic error is typing:
% rm * .o
% rm *.o
./- Section 14.13
% touch ./-i
In this case, the * is expanded to match all of the filenames in the directory. Because the file -i is alphabetically listed before any file except those that start with one of the characters !, #, $, %, &, ', ( , ), *, +, or ,, the rm command sees the -i file as a command-line argument. When rm is executed with its -i option, files will not be deleted unless you verify the action. This still isn't perfect, though. If you have a file that starts with a comma (,) in the directory, it will come before the file starting with a dash, and rm will not get the -i argument first.
The -i file also won't save you from errors like this:
% rm [a-z]* .o
If lots of users each make a -i file in each of their zillions of subdirectories, that could waste a lot of disk inodes (Section 14.2). It might be better to make one -i file in your home directory and hard link (Section 15.4) the rest to it, like this:
% cd % touch ./-i % cd somedir % ln ~/-i . ...
Second, to save disk blocks, make sure the -i file is zero-length -- use the touch command, not vi or some other command that puts characters in the file.
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