What is the /~ file on Mac OS X? In the root directory of my Mac (10.10.4) I see a file named just ~ (tilde):  $ ls -l /~ -rw-------  2 root  wheel  2187264 Mar 23 22:33 /~   file just reports it as "data". For reference, here are the first 256 bytes as seen through xxd:  0000000: d0fa d0da 0010 0000 2800 0000 9002 0000  ........(....... 0000010: 1b00 0000 0000 0000 0c00 0000 2c00 0000  ............,... 0000020: ca02 0000 0000 0000 0e00 0000 0000 0000  ................ 0000030: 3c63 6174 616c 6f67 3e00 0000 0b00 0000  &lt;catalog&gt;....... 0000040: 0010 0000 5374 7269 6e67 0000 0a00 0000  ....String...... 0000050: 0010 0400 4172 7261 7900 0000 0b00 0000  ....Array....... 0000060: 0090 0500 4275 6e64 6c65 0000 0a00 0000  ....Bundle...... 0000070: 0010 0700 436c 6169 6d00 0000 0c00 0000  ....Claim....... 0000080: 0090 0800 5365 7276 6963 6500 0900 0000  ....Service..... 0000090: 00a0 0800 5479 7065 0000 0000 0f00 0000  ....Type........ 00000a0: 00a0 0900 5554 4942 696e 6469 6e67 0000  ....UTIBinding.. 00000b0: 1500 0000 0020 0a00 4578 7465 6e73 696f  ..... ..Extensio 00000c0: 6e42 696e 6469 6e67 0000 0000 1200 0000  nBinding........ 00000d0: 00a0 0a00 4f53 5479 7065 4269 6e64 696e  ....OSTypeBindin 00000e0: 6700 0000 1000 0000 00e0 0a00 4d49 4d45  g...........MIME 00000f0: 4269 6e64 696e 6700 1800 0000 0000 0b00  Binding.........   It appears to be full of file paths and extensions, along with a lot more filesystem data. Is this a standard file to have on OS X, and if so what is its purpose? If it's not a standard file, any ideas of what created it?
Tilde (~) File in Macintosh Directory Last night I discovered what looks like an unusual file named "~" (tilde) in the root of my "Macintosh HD" directory on my MacBook.    Finder reports the file is 2.2MB in size, of kind "TextEdit.app Document", and was created on 22nd January 2014 (so about a month ago).  I haven't noticed any operational issues with OS X or it's applications.   I haven't yet touched the file but would obviously like to remove it.  I am very conscious that '~' is a special alias to the user home directory and thus I would appreciate any recommendations in removing the file in a safe manner that isn't likely to nuke my home directory or screw up the operation of applications or OS X. I don't know whether to delete or rename and whether to use Finder or the command line.   It's entirely possible that I created the file by accident since I've recently been drafting and running various shell scripts that use the ~, user home alias.  MacBook Pro 15" (Retina, Mid 2012) Yosemite
Generic constraints, where T : struct and where T : class I'm looking into developing an ordering app for a potential client. The main part that I'm concerned about in this question is the payment mechanism. I would assume that there are already multiple plugins or similar programs out there, but I'm not sure where (or if) I should be asking for recommendations. I use Stack Overflow a lot and have noticed a certain trend that I myself got caught up in at one time of using the phrase "I am having a problem" in place of "I have a problem."  I would use this phrase for an event in the future, for example, "I am having a steak dinner tonight," but for a problem that I need solved and am asking for a solution, I'd use "I have a problem..."   What would force us to use this phrase? Is it even valid English for the present tense? How do I setup keyboard macros? In my daily life I'm always typing &lt;kbd&gt;Keyboard Character&lt;/kbd&gt; and I'd like to set up a macro in Ubuntu to automatically enter &lt;kbd&gt; &lt;/kbd&gt;.  I'd like to assign it to say Shift+Control+K or whatever keyboard control character combination isn't assigned and already used by Ubuntu.  Back in the day of TSR (Terminate and Stay Resident) MS-DOS programs this was possible. Certainly it must be in Ubuntu too?  Do I have to write a daemon to accomplish this?    I found other questions with no answers: ,   I found a similar question with an answer: . However that question stipulated the answer could not be AutoKey. Linux file access monitoring Is there any way in unix to find out who accessed certain file in last 1 week? It may be user or some script ftp it to some other place. Can I get a list of user name who accessed certain file? How can I find out who is accessing particular file?? Regular expression to match balanced parentheses Parse error in sudoers file When should "into" be used rather than "in to," and vice versa? "Into" (one word) and "in to" (two words) are frequently confused.  In what situations should the former be used?  The latter? I am creating a model of a glass and I would like to put a drawing on it (a png picture).  I know how to do it using Blender Render, but not with Cycles Render. Help :) Blackboard bold characters The blackboard bold font in the AMSFonts package only has capital letters.  I sometimes wish to use a blackboard bold "1", for which I can use \usepackage{bbold}. But this changes the entire blackboard bold font, and I like the original AMSFonts versions of the capital letters better.  Is there a simple way for me to get \mathbb{1} from one package and the blackboard bold capitals from another? What does 'exec {fd}</dev/watchdog' do in Bash That is literal, {fd} isn't a placeholder. I have a script that does this, and does not source in anything, nor does it reference {fd} anywhere else.  Is this valid bash?  exec {fd}&lt;/dev/watchdog Label callouts in QGIS Has anyone been using callout labelling with QGIS, either trunk or stable?   Used for clustered points. That means the point stays where it is, the label maybe moved if required and a leader (plain or pointed) shows the linkage between the label and the point.   How could I do it (you know what I mean, no coding....)? What's the best way to draw UML class diagrams in LaTeX? I always stumble when using abbreviations in a sentence, as they inherently contain a period in them. How do I use a comma or a semicolon after an abbreviation? How about a period?  E.g. (This is an example of my quandary) Scanf skips every other while loop in C Why do positive and negative variants of the same question elicit the same answer? My installation is a Ubuntu 12.04 64 bits (Classic "legacy" MBR - No  EFI/UEFI here) with two partition :   A separate boot partition An encrypted LUKS volume that contains the system Logical Volumes   I seems I accidentaly deleted all the current kernel files with:  sudo apt-get purge 'linux-image-3.8*'    I applied the updates with Ubuntu Software Update, rebooted and then: Ubuntu can't boot.  I tried to boot on a live DVD with a 14.04.1 Ubuntu and can still see my partitions (described later):  /dev/sda1 (boot) /dev/sda2 (Encrypted volume) /dev/sda5 (Logical Volume container)  What are the steps to recover/reinstall the kernel files and dependencies in order to cleanly reboot my installed system?  Thanks in advance Very good linear algebra book. I plan to self-study linear algebra this summer. I am sorta already familiar with vectors, vector spaces and subspaces and I am really interested in everything about matrices (diagonalization, ...), linear maps and their matrix representation and eigenvectors and eigenvalues. I am looking for a book that handles every of the aforementioned topics in details. I also want to build a solid basis of the mathematical way of thinking to get ready to an exciting abstract algebra next semester, so my main aim is to work on proofs for somehow hard problems. I got Lang's "Intro. to Linear Algebra" and it is too easy, superficial.  Can you advise me a good book for all of the above? Please take into consideration that it is for self-study, so that it' gotta work on its own. Thanks. Are PHP variables passed by value or by reference? Parallel universes: are there an infinite amount of universes? Parallel universe: in every universe, you are presented with a different decision. Does that mean there are an infinite amount of parallel universes? 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