Safer File Deletion in Some Directories
Using noclobber () and read-only files only protects you from a few occasional mistakes. A potentially catastrophic error is typing:
%rm * .o
instead of:
%rm *.o
In the blink of an eye, all of your files would be gone. A simple, yet effective, preventive measure is to create a file called -i in the particular directory in which you want extra protection:
touch /- |
% |
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In the above 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 these characters: !#$%&`()*+,, 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. 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:
%rm [a-z]* .o
[Two comments about Bruce's classic and handy tip: first, if lots of users each make a -i file in each of their zillions of subdirectories, that could waste a lot of disk inodes (). It might be better to make one -i file in your home directory and hard link () the rest to it, like:
~ |
% |
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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. -JP ]
- BB