If some user is an owner of some file, does root has the same privileges as user?
I have the following file:  ---------- 1 Steve Steve 341 2017-12-21 01:51 myFile.txt   I switched the user to root in the terminal, and I have noticed the following behaviors:   I can read this file and write to it. I can't execute this file. If I set the x bit in the user permissions (---x------) or the group permissions (------x---) or the others permissions (---------x) of the file, then I would be able to execute this file.   Can anyone explain to me or point me to a tutorial that explains all of the rules that apply when the root user is dealing with files and directories?
This should be a fairly trivial problem. I'm trying to open an ofstream using a std::string (or std::wstring) and having problems getting this to work without a messy conversion.  std::string path = ".../file.txt";  ofstream output;  output.open(path);   Ideally I don't want to have to convert this by hand or involve c-style char pointers if there's a nicer way of doing this? Proving that if $ad-bc = \pm 1$, then $\gcd(x,y) = \gcd(ax +by, cx + dy)$ I'm having issues figuring out how to approach this problem:     Conclude that if $ad-bc = \pm 1$, then   $$\gcd(x,y) = \gcd(ax +by, cx + dy)$$   The fact that $\gcd(x,y) = \gcd(x+ky, y)$ is a very special case of this exercise   I believe there is a property that if $a = bq_1 + 0$ where 0 is r, then b divides a, and $b=\gcd(a,b)$  Is that at all relevant in this case? Where can I find a repository for older unsupported releases? How to sort a character vector where elements contain letters and numbers in R? My earliest PhD graduation date is 10 months away. Funding permits me to stay 1–3 months longer, so the final date is still uncertain.  It is never too early to make contacts for possible post-docs. But how long in advance is too early to formally apply to post-doc job openings or funding opportunities? Depending on the bureaucracy, the path from applying to starting can probably be anything from a week up to a year — someone I know is applying with  which had the opening advertised in August, application deadline in October, will have interviews in December/January, and the commencement of work only in September, 13 months after the initial job advertisement. My personal guess is that the long time between interviews and starting is to create a level playing field between those who do and those who don't need to go through a visa application procedure.  If I'm too early in applying for a post-doc, a hosting institution might prefer someone who can start earlier and where the graduation date is more certain. For example, in my case the graduation date is still uncertain, so there is a risk in accepting even if they are willing to wait. Project funding might also require the money to be spent rather soon.  If I wait too long, there might be a considerable period where I'm between jobs. Having a long (>6 months) period between jobs is a disadvantage for me. Maybe it's also a disadvantage for a hosting institution (I'm not sure).  How do I find the balance? For example, considering the duration of funding and visa applications, does it make sense to apply e.g. ? Or is it in any case virtually inevitable to have at least several months before my PhD graduation and the start of a post-doc? If $G$ is a group and $G'$ is generated by $\{xyx^{-1}y^{-1}|x,y\in G\}$, then $G'\trianglelefteq G$ and  $G/G'$ is Abelian.  At first, I thought this is easy because I thought $g[x,y]g^{-1}=[gxg^{-1},gyg^{-1}]$. But it was a mistake. I could not prove that it is also subgroup of G and $G/G'$ is abelian. I need help. Over on another network site, a helpful user corrected the grammar of .  The answer now says     I believe it's valid.   where I originally wrote     I believe it valid.   Is the original sentence gramamatically (or at least idiomatically) correct or do I absolutely need a form of 'to be' here? (What's more, is 'to be' a copula or an auxiliary verb if used like this?)  I am quite certain that I have seen sentences like the original one in the past, but I am uncertain where. Given that I am frequently exposed to the somewhat made-up English of authors in the fields of sci-fi and fantasy, I might have fallen into a trap here.  Edit: I don't doubt that the correction is valid and enhances readability. Case insensitive regular expression without re.compile? In Python, I can compile a regular expression to be case-insensitive using re.compile:  &gt;&gt;&gt; s = 'TeSt' &gt;&gt;&gt; casesensitive = re.compile('test') &gt;&gt;&gt; ignorecase = re.compile('test', re.IGNORECASE) &gt;&gt;&gt;  &gt;&gt;&gt; print casesensitive.match(s) None &gt;&gt;&gt; print ignorecase.match(s) &lt;_sre.SRE_Match object at 0x02F0B608&gt;   Is there a way to do the same, but without using re.compile. I can't find anything like Perl's i suffix (e.g. m/test/i) in the documentation. I play D&amp;D 5e and sometimes come here with questions. But sometimes I see things referenced here as sources that I don't have or aren't aware of....  Which are the "official rules" for D&amp;D 5e, and where do I find them? what are all the open subgroups of $(\mathbb{R},+)$ Why does ice melting not change the water level in a container? I have read the explanation for this in several textbooks, but I am struggling to understand it via Archimedes' principle. If someone can clarify with a diagram or something so I can understand or a clear equation explanation that would be great. I worked, I've worked, I have been working. I need some clarifications Could you help me with these sentences:   I lied to her. (I'm just making a statment)  I've lied to her because the truth would have hurted her.   Second example:   I have been working at Google for 10years. (Meaning I am still working there) I've worked at Google and it was nice.(I don't work anymore) I worked at Google. (Not sure about the difference with the previous one)   I'm learning the different tenses and it isn't so easy for me. Any help would be welcome.  Regards, What's everyone's opinion on closing an older question as a duplicate of a newer one, if the newer one is clearly the better resource? I'm looking at a special case right now, where the two were posted by the same person; the  was migrated to SU before a commenter pointed out it was a . Is it considered good practice to close the older as a duplicate of the newer?  More generally, is it ok to do that for separate questions posted by different people, if the older question went unanswered but the newer has a good answer?  (I should probably mention I saw , but I think this is separate) If you want to buy a house but you also think value will drop… is there something you can do to alleviate the risk? Disclaimer: yours won't be fiscal advice. People involved will consult a professional before doing anything. This is just to gather some preliminary information.  Situation:   you want to buy a house or a flat, in UK you will get a mortgage in GBP, but you'd pay the down payment in EUR you think that there are fairly high chances that the value of houses in UK and GBP will drop the whole point of this question is actually buying the house/flat, renting is not an option by definition   What can you do to mitigate that risk? How can I manipulate field-based data from the commandline? For example   How can I print only lines whose Nth field is foo? How can I print only lines whose Nth field isn't foo? How can I print only lines whose Nth field matches foo? How can I change field N to foo?   Is there a standard approach or toolset that facilitates manipulating field-based data on *nix systems? I have a HP Pavilion dm4-2070us which has an Intel Corporation Centrino Wireless-N 1000 adapter.   The problem is that my computer doesn't show the wireless networks after I upgraded my system to Ubuntu 11.10. Following is my output for sudo lshw -class network:  *-network DISABLED          description: Wireless interface    product: Centrino Wireless-N 1000    vendor: Intel Corporation    physical id: 0    bus info: pci@0000:01:00.0    logical name: wlan0    version: 00    serial: 8c:a9:82:81:5a:30    width: 64 bits    clock: 33MHz    capabilities: pm msi pciexpress bus_master cap_list ethernet physical wireless    configuration: broadcast=yes driver=iwlagn driverversion=3.0.0-12-generic firmware=39.31.5.1 build 35138 latency=0 link=no multicast=yes wireless=IEEE 802.11bgn    resources: irq:42 memory:c2500000-c2501fff  *-network    description: Ethernet interface    product: AR8151 v2.0 Gigabit Ethernet    vendor: Atheros Communications    physical id: 0    bus info: pci@0000:08:00.0    logical name: eth0    version: c0    serial: 2c:41:38:07:f3:e3    size: 100Mbit/s    capacity: 1Gbit/s    width: 64 bits    clock: 33MHz    capabilities: pm msi pciexpress vpd bus_master cap_list ethernet physical tp 10bt 10bt-fd 100bt 100bt-fd 1000bt-fd autonegotiation    configuration: autonegotiation=on broadcast=yes driver=atl1c driverversion=1.0.1.0-NAPI duplex=full firmware=N/A ip=192.168.1.7 latency=0 link=yes multicast=yes port=twisted pair speed=100Mbit/s    resources: irq:44 memory:c1400000-c143ffff ioport:2000(size=128)   The output for rfkill list all:  0: hp-wifi: Wireless LAN     Soft blocked: no     Hard blocked: no 1: hp-bluetooth: Bluetooth     Soft blocked: no     Hard blocked: no 2: phy0: Wireless LAN     Soft blocked: no     Hard blocked: no 3: hp-wwan: Wireless WAN     Soft blocked: no     Hard blocked: no   I have also searched about the status of the WiFi network being shown as disabled. Somehow everything pointed to the fact that my wireless device is switched off and it can be switched on from Windows only. However, I don't have windows partition and it has just Ubuntu 11.10 so I don't see any point in switching the device on in Windows. I was just looking at the statistics for migrated questions in the  mod tools, and noticed this oddity:    The actual statistics, as visible to any 10k+ SFF user , are: 6 migrated to Worldbuilding, 2 to Literature, 2 to SFF meta, 1 to Movies &amp; TV, 1 to Writers, and 1 to Aviation.  Why is one of the meta migrations showing up with a blank icon rather than with the other?  Both migrated questions were closed as duplicates on meta. Both were migrated by 5 community members without mod involvement. One of the stubs on main has since been deleted, but so have the stubs for some of the other migrated questions. I can't think of anything to explain this discrepancy. Equivalent statement of AC or not? Here's a corollary of AC stating that: if there exists an onto mapping $f:A\to B$, then there exists a 1-1 mapping $g:B\to A$. What I'm confused about is that whether or not  AC can be derived from this proposition, in return? I have tried but haven't found a proof. Any help would be appreciated. What is the la command? I just mistyped ls as la. Without noticing, I ran it:  tim@Hairy:~$ la detection.sh   output-2.jpg  output-4.jpg  output-6.jpg  output-8.jpg Test1.pdf output-1.jpg   output-3.jpg  output-5.jpg  output-7.jpg  output-9.jpg          tim@Hairy:~$ ls detection.sh   output-2.jpg  output-4.jpg  output-6.jpg  output-8.jpg Test1.pdf output-1.jpg   output-3.jpg  output-5.jpg  output-7.jpg  output-9.jpg    What's the difference between ls and la? Is it possible to make a sequence of renders and give the user the option to cancel the process through the UI at any given time? I'm trying to make a script where I have to render several images of the same scene at the same frame, and write to disk with appropriate names. The problem is that although this works fine with a non-responsive UI, it doesn't work well when the render progress appears in the Blender UI.  I mean,  bpy.ops.render.render()   uses "EXEC_DEFAULT" when called from a script. This leaves a blocked User Interface until the render finishes, meaning that you can't cancel the process, except by killing Blender. The problem is that the render may be too big in resolution, and the user could want to stop the process when realizing that the render could take hours, so the idea is to cancel this process without losing the currently opened project.  If I call,  bpy.ops.render.render("INVOKE_DEFAULT")   I get a nice preview bar in the Info Window with a clickable "X" button. I want the user to be able to press that button to cancel the operation if needed, but for a series of renders (not animation).  The problem here seems to be when trying to loop this command with the INVOKE_DEFAULT context to write several renders. I made a lot of testing, and this way of calling the render operator seems to continue with whatever is next in the script, so it loops very fast and ends before the rendering actually finishes.  I think that I need some way to stop the script and make it wait until render finishes to continue looping with the next ones. I tried the "render_complete" and "render_cancel" handlers, but I can't use them to start a new render or even make the rest of the script wait until the loop of renders is complete. I tried threading and events without success either. Maybe I'm doing something wrong.  import bpy  render = bpy.context.scene.render path = render.filepath = "/tmp/" shots = ["one", "two", "three"]  for x in shots:     render.filepath = path + x     bpy.ops.render.render("INVOKE_DEFAULT", write_still=True) # this doesn't work      # but if I use:     # bpy.ops.render.render(write_still=True)     # without the INVOKE thing, images are written as expected,     # but losing the possibility to see the progress and cancel rendering