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Unix - Frequently Asked Questions (2/7) [Frequent posting]
Section - How do I remove a file with funny characters in the filename ?

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2.2)  How do I remove a file with funny characters in the filename ?

      If the 'funny character' is a '/', skip to the last part of this
      answer.  If the funny character is something else, such as a ' '
      or control character or character with the 8th bit set, keep reading.

      The classic answers are

        rm -i some*pattern*that*matches*only*the*file*you*want

        which asks you whether you want to remove each file matching
        the indicated pattern;  depending on your shell, this may not
        work if the filename has a character with the 8th bit set (the
        shell may strip that off);

      and

        rm -ri .

        which asks you whether to remove each file in the directory.
        Answer "y" to the problem file and "n" to everything else.
        Unfortunately this doesn't work with many versions of rm.  Also
        unfortunately, this will walk through every subdirectory of ".",
        so you might want to "chmod a-x" those directories temporarily
        to make them unsearchable.

        Always take a deep breath and think about what you're doing and
        double check what you typed when you use rm's "-r" flag or a
        wildcard on the command line;

      and

        find . -type f ... -ok rm '{}' \;

      where "..." is a group of predicates that uniquely identify the
      file.  One possibility is to figure out the inode number of the
      problem file (use "ls -i .") and then use

        find . -inum 12345 -ok rm '{}' \;

      or
        find . -inum 12345 -ok mv '{}' new-file-name \;
        
      "-ok" is a safety check - it will prompt you for confirmation of
      the command it's about to execute.  You can use "-exec" instead
      to avoid the prompting, if you want to live dangerously, or if
      you suspect that the filename may contain a funny character
      sequence that will mess up your screen when printed.

      What if the filename has a '/' in it?

      These files really are special cases, and can only be created by
      buggy kernel code (typically by implementations of NFS that don't
      filter out illegal characters in file names from remote
      machines.)  The first thing to do is to try to understand exactly
      why this problem is so strange.

      Recall that Unix directories are simply pairs of filenames and
      inode numbers.  A directory essentially contains information
      like this:

        filename  inode

        file1     12345
        file2.c   12349
        file3     12347

      Theoretically, '/' and '\0' are the only two characters that
      cannot appear in a filename - '/' because it's used to separate
      directories and files, and '\0' because it terminates a filename.

      Unfortunately some implementations of NFS will blithely create
      filenames with embedded slashes in response to requests from
      remote machines.  For instance, this could happen when someone on
      a Mac or other non-Unix machine decides to create a remote NFS
      file on your Unix machine with the date in the filename.  Your
      Unix directory then has this in it:

        filename  inode

        91/02/07  12357

      No amount of messing around with 'find' or 'rm' as described
      above will delete this file, since those utilities and all other
      Unix programs, are forced to interpret the '/' in the normal way.

      Any ordinary program will eventually try to do
      unlink("91/02/07"), which as far as the kernel is concerned means
      "unlink the file 07 in the subdirectory 02 of directory 91", but
      that's not what we have - we have a *FILE* named "91/02/07" in
      the current directory.  This is a subtle but crucial distinction.

      What can you do in this case?  The first thing to try is to
      return to the Mac that created this crummy entry, and see if you
      can convince it and your local NFS daemon to rename the file to
      something without slashes.

      If that doesn't work or isn't possible, you'll need help from
      your system manager, who will have to try the one of the
      following.  Use "ls -i" to find the inode number of this bogus
      file, then unmount the file system and use "clri" to clear the
      inode, and "fsck" the file system with your fingers crossed.
      This destroys the information in the file.  If you want to keep
      it, you can try:

        create a new directory in the same parent directory as the one
        containing the bad file name;

        move everything you can (i.e. everything but the file with the
        bad name) from the old directory to the new one;

        do "ls -id" on the directory containing the file with the bad
        name to get its inumber;

        umount the file system;

        "clri" the directory containing the file with the bad name;

        "fsck" the file system.

      Then, to find the file,

        remount the file system;

        rename the directory you created to have the name of the old
        directory (since the old directory should have been blown away
        by "fsck")

        move the file out of "lost+found" into the directory with a
        better name.

      Alternatively, you can patch the directory the hard way by
      crawling around in the raw file system.  Use "fsdb", if you
      have it.

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Top Document: Unix - Frequently Asked Questions (2/7) [Frequent posting]
Previous Document: How do I remove a file whose name begins with a "-" ?
Next Document: How do I get a recursive directory listing?

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Last Update March 27 2014 @ 02:12 PM