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Aug. 10, 2020 Update Fordham Forward, the plan to resume in-person teaching and learning on Aug. 26, is available below, along with extensive resources for students, parents, faculty, and staff. Full Details

Keeping Skulker from Deleting Files

Here is how to prevent skulker from deleting files you want to keep. Apart from the obvious answer of avoiding ''junk'' names for precious files, there are two standard answers to this.

  • Read-only permission. By default, files generally are created with owner-write permission. If you turn off this permission, skulker will leave the files alone. You can see what permission a file has by using the ''ls -l'' command. For example, if you see this:
    -rw-r--r-- 1 joeuser students 8165 Mar 20 16:47 foo.o
    -r--r--r-- 1 joeuser students 4060 Mar 20 17:14 bar.o

    foo.o has owner-write permission turned on, and bar.o has it turned off. To turn off write permission on foo.o, just use the command ''chmod -w foo.o''. To turn write permission back on, change the ''-w'' to ''+w'' in that command.
  • Special directories. Executable files are protected from deletion by skulker if they are located in certain special directories, namely any directory named ''bin'', ''sbin'', ''cgi-bin'', ''lib'', or ''libexec''. Object files are protected if they are in a directory named ''lib''. MPEG files are protected if they are in a directory named public_html. Files are also protected in any subdirectory of one of these directories.

    If you have a favorite executable program that you want to keep permanently, the best thing to do is to create a ''bin'' directory in your home directory and place the executable there. To make this program accessible no matter what directory you are in, add ''$HOME/bin'' to your path. This step is easily accomplished by editing the file .cshrc in your home directory.

Finally, don't panic! skulker has no interest in deleting C source files, Perl programs, mailboxes, text files, html files, etc. These can be left lying around for as long as you wish.