tags 42440 + notabug thanks ���� wrote: > sometimes,rm can't delete the file. > but when using rm -rf + file . > the file can be deleted.
This does not sound like a bug in the rm command. Therefore I am tagging this as such. If you have follow up information and this turns out to be an actual bug then we can reopen the bug report. Unfortunately there is not enough information in the report to know exactly the case that you are talking about. For example I don't know if you are talking about a literal "+" in that line or not. I will assume that you are since it is there. There are several FAQs listed for rm. Any of these might be a problem. https://www.gnu.org/software/coreutils/faq/coreutils-faq.html#How-do-I-remove-files-that-start-with-a-dash_003f https://www.gnu.org/software/coreutils/faq/coreutils-faq.html#Why-doesn_0027t-rm-_002dr-_002a_002epattern-recurse-like-it-should_003f You might have experienced either of those problems. Or a different problem. We can't tell. > sometimes,rm can't delete the file. There are two main cases. One is that if the file is not writable by the user then 'rm' will check for this and ask the user for confirmation. rwp@angst:/tmp/junk$ touch file1 rwp@angst:/tmp/junk$ chmod a-w file1 rwp@angst:/tmp/junk$ rm file1 rm: remove write-protected regular empty file 'file1'? n rwp@angst:/tmp/junk$ ls -l file1 -r--r--r-- 1 bob bob 0 Jul 21 23:52 file1 The -f option will force it without prompting. rwp@angst:/tmp/junk$ rm -f file1 rwp@angst:/tmp/junk$ ls -l file1 ls: cannot access 'file1': No such file or directory This is a courtesy confirmation. Because the permissions on the file is not important when it comes to removing a directory entry. A file is really just an entry in the directory containing it. Removing a file simply removes the entry from the directory. When the last link to the file reaches zero then the file system reclaims the storage. The file system is a "garbage collection" system using reference counting. https://en.wikipedia.org/wiki/Garbage_collection_(computer_science) Therefore the only permission needed to remove a file is write permission to the directory containing it. rwp@angst:/tmp/junk$ touch file2 rwp@angst:/tmp/junk$ ls -ld . file2 drwxrwxr-x 3 rwp rwp 100 Jul 21 23:56 ./ -rw-rw-r-- 1 rwp rwp 0 Jul 21 23:56 file2 rwp@angst:/tmp/junk$ chmod a-w . rwp@angst:/tmp/junk$ ls -ld . file2 dr-xr-xr-x 3 rwp rwp 100 Jul 21 23:56 ./ -rw-rw-r-- 1 rwp rwp 0 Jul 21 23:56 file2 This creates a file. The file is writable. But I have changed the directory containing it not to be writable. This prevents the ability to remove the file. Can't remove it because the directory is not wriable. rwp@angst:/tmp/junk$ rm file2 rm: cannot remove 'file2': Permission denied rwp@angst:/tmp/junk$ rm -f file2 rm: cannot remove 'file2': Permission denied rwp@angst:/tmp/junk$ rm -rf file2 rm: cannot remove 'file2': Permission denied rwp@angst:/tmp/junk$ ls -ld . file2 dr-xr-xr-x 3 rwp rwp 100 Jul 21 23:56 ./ -rw-rw-r-- 1 rwp rwp 0 Jul 21 23:56 file2 In order to remove the file we must have write permission to the directory. Adding write permission to the directory allows removing the file. rwp@angst:/tmp/junk$ chmod ug+w . rwp@angst:/tmp/junk$ rm file2 rwp@angst:/tmp/junk$ ls -ld file2 ls: cannot access 'file2': No such file or directory Expanding upon this problem is if there are many directories deep and the directories are not writable. rwp@angst:/tmp/junk$ mkdir -p dir1 dir1/dir2 dir1/dir2/dir3 rwp@angst:/tmp/junk$ touch dir1/dir2/dir3/file3 rwp@angst:/tmp/junk$ chmod -R a-w dir1 rwp@angst:/tmp/junk$ find dir1 -ls 69649132 0 dr-xr-xr-x 3 rwp rwp 60 Jul 22 00:00 dir1 69649133 0 dr-xr-xr-x 3 rwp rwp 60 Jul 22 00:00 dir1/dir2 69649134 0 dr-xr-xr-x 2 rwp rwp 60 Jul 22 00:00 dir1/dir2/dir3 69650655 0 -r--r--r-- 1 rwp rwp 0 Jul 22 00:00 dir1/dir2/dir3/file3 That sets up the test case. None of the directories are wriable. Therefore we cannot remove any of them. The directory holding the entries must be writable. rwp@angst:/tmp/junk$ rm -rf dir1 rm: cannot remove 'dir1/dir2/dir3/file3': Permission denied Even using 'rm -rf' does not work. And should not work. Because the directories are not writable. In order to remove these files the directories must be made writable. rwp@angst:/tmp/junk$ chmod -R u+w dir1 rwp@angst:/tmp/junk$ rm -rf dir1 rwp@angst:/tmp/junk$ ls -ld dir1 ls: cannot access 'dir1': No such file or directory Hopefully this helps you understand how directory entries work, that the directory holding an entry (either file or another directory) must be writable. How to add write permission. How to remove a single file. How to remove a directory tree. Hopefully this helps! :-) Bob
