wondering if you can use a late 2013 iMac as an external monitor to a 2020 27inch iMac.i spoke to the office supplies tech guy who recommended a thunder port 2 cable but that fits in the 2013 not the 2020 which is a thunderbolt 3! Can this be done? I know there seems to be all sorts of caveats for different models. What I think I need is a cable with a thunderbolt 3 on one end and a thunderbolt 2 in the other but as they don’t seem to exist...any suggestions would be greatly appreciated!!
I have a Surface Pro 4 and an iMac (late 2019). I would like to connect my Surface Pro to the iMac to use the iMac screen as a second monitor.  Is that possible?  What are the requirements to use an iMac as a second screen?
Joined pipelines Considering a routine such as this one:  alpha() { echo a b c |tr ' ' '\n'; }   which outputs a stream, I would like to take the output stream, transform it, and paste it with the original output stream.  If I take use upcasing as a sample transformation, I can achieve what I want with:  $ mkfifo p1 p2 $ alpha | tee p1 &gt;( tr a-z A-Z &gt; p2) &gt;/dev/null &amp; $ paste p1 p2 a       A b       B c       C   My question is, is there a better way to do this, preferably one not involving named pipes? meaning of -h in ls command Proof that all abelian simple groups are cyclic groups of prime order If I know for two numbers a and b that    $${a &lt; b }$$  Then is it correct to say that    $$ a \leq b $$  I know that the second statement is true as long as the first one is. It seems OK as it is true but from the other side it seems kinda weird (to me), to say that, if you know, that a is strictly less that b.It's like you lose some extra information. Let $E$ be a finite dimensional vector space over field $\mathbb R$ with $E^*$ as the dual space of $E$.($\dim E=n$)   $\Omega^P(E):=\{ \alpha\colon \overbrace{E\times\cdots\times E}^{p- times}\rightarrow \mathbb R\  \ , \alpha \text{ is alternating multilinear map}\}$ $\Omega^P(E^*):=\{ u\colon \overbrace{E^*\times\cdots\times E^*}^{p- times}\rightarrow \mathbb R\  \ , u \text{ is alternating multilinear map}\}$  I wish to prove that there exist an $\textbf{unique}$ bilinear form $B\colon \Omega^p(E^*)\times\Omega^p(E)\rightarrow\mathbb R$   such that for all $ f_i\in E^* \ , u_j\in E^{**}\simeq E \qquad  i,j=1,\cdots,p$, it has the following rule:  $B(u_1\wedge\cdots\wedge u_p,f_1\wedge\cdots\wedge f_p)=\det[f_i(u_j)]$.  $\wedge$ is wedge product between alternating maps i.e. $\alpha\wedge\beta(v_1,\cdots,v_{p+p})=\dfrac{1}{p! p!}\displaystyle\sum_{\sigma\in S_{p+p}}sign(\sigma)\alpha(v_{\sigma(1)},\cdots,v_{\sigma(p)})\beta(v_{\sigma(p+1)},\cdots,v_{\sigma(p+p)})$  How can I do this? I have an 3TB external disk and Windows XP 32 bit. It works as a USB 2 disk with its enclosure, but I want to use it as an internal SATA disk. I don't want to use it as a boot disk, only as a data disk. I understand that normally I need GPT (GUID partition table), and then I can't use Windows XP 32 bit anymore. I would prefer to avoid this. But what I did not understand by googling around is: can I partition the disk in 2 parts (so that each part is less than 2TB) with MBR and use it in Windows 32-bit? If yes, which tools do I need? Prove that $Z(G)$ which is the center of $G$ is a subgroup of $G$ Solve $[2^{(2^{403})}] = [a]$ in $\mathbb Z_{23}$ where $0 \le a < 23$. Solve $[2^{(2^{403})}] = [a]$ in $\mathbb Z_{23}$ where $0 \le a &lt; 23$.  I've tried to combine corollaries of Fermat's little theorem and various other methods to solve this, but have always been stuck. While browsing on Safari and listening to iTunes I come across a video and then press the "play" button on the keyboard (to stop the music while I watch the video) it starts/stops the video instead of the music (I have no control over the music).  How can I quickly play/pause my music without affecting the video? Order of a homomorphism of groups Before I met her I had a poor opinion of her.   As person had a poor opinion before a particular time in past (before He met her) so I think there should be had had.   There are some more example like this:   Before I went to the university, I worked/had worked as a carpenter for 5 years. Before I opened the door, I put/had put the key in the lock. Before I opened the door, I looked/had looked carefully into the barn for snipers.   In all these sentence, for me, it should be perfect tense.  I asked that question on another platform where I was told that if sequence of past event is obvious and sentences uses "before"and "after", we often use past tense. Which means we should use past tense in all these sentences. But I have another sentence "The train had left before I reached the station." If I follow above mentioned rule there should be "left" instead of "had left". But I am damn sure this sentence is correct with "had left".   Am I correct?  Thank you I am pretty sure that this is such a stupid, stupid question, but how do you prove that $d_2(x,y)={|x-y|\over {1+|x-y|}}$ satisfying the third condition to be a metric, which is the triangle inequality.   I know that I should really be able to do this, but I just can't, I keep seeing a contradiction. Please help me. Recently, the titles to some questions have been displaying as "undefined":    "undefined" is replaced with the question's true title upon refreshing the page. Is this a bug? What is the difference between [@] and [*] when referencing bash array values? says:  If the index number is @ or *, all members of an array are referenced.  When I do this: LIST=(1 2 3) for i in &quot;${LIST[@]}&quot;; do   echo &quot;example.$i&quot; done  it gives the desired result: example.1 example.2 example.3  But when I use ${LIST[*]}, I get example.1 2 3  instead. Why? Edit: when using printf, @ and * actually do give the same results. I have asked this question before ( and  )  My problem is that my Self Encrypted Disk (SED) have to NOT spin down even on suspend!  I have tried , but it did not work and the disk spin downs anyway !  The problem is that if the disk spins down, because it is on suspend, it does not show the "de encryption" prompt, and boots back up on RAM, but crashed due to IO error on the disk! (that's what the disk is suposed to do !)  Anyone on how to NOT (as in NEVER) spin down a HDD ? (yes this goes against all logic but this particular case)   Thanks a lot !  Would that be useful ?   sudo hdparm -I /dev/sda [sudo] password for xqua:   /dev/sda:  ATA device, with non-removable media     Model Number:       ST500LT015-9WU142                            Serial Number:      W0VBZQQ7     Firmware Revision:  0001SDM7     Transport:          Serial, ATA8-AST, SATA 1.0a, SATA II Extensions, SATA Rev 2.5, SATA Rev 2.6 Standards:     Used: unknown (minor revision code 0x0029)      Supported: 8 7 6 5      Likely used: 8 Configuration:     Logical     max current     cylinders   16383   16383     heads       16  16     sectors/track   63  63     --     CHS current addressable sectors:   16514064     LBA    user addressable sectors:  268435455     LBA48  user addressable sectors:  976773168     Logical  Sector size:                   512 bytes     Physical Sector size:                  4096 bytes     Logical Sector-0 offset:                  0 bytes     device size with M = 1024*1024:      476940 MBytes     device size with M = 1000*1000:      500107 MBytes (500 GB)     cache/buffer size  = 16384 KBytes     Form Factor: 2.5 inch     Nominal Media Rotation Rate: 5400 Capabilities:     LBA, IORDY(can be disabled)     Queue depth: 32     Standby timer values: spec'd by Standard, no device specific minimum     R/W multiple sector transfer: Max = 1   Current = 1     Advanced power management level: 254     Recommended acoustic management value: 208, current value: 0     DMA: mdma0 mdma1 mdma2 udma0 udma1 udma2 udma3 udma4 udma5 *udma6           Cycle time: min=120ns recommended=120ns     PIO: pio0 pio1 pio2 pio3 pio4           Cycle time: no flow control=120ns  IORDY flow control=120ns Commands/features:     Enabled Supported:        *    SMART feature set        *    Power Management feature set        *    Write cache        *    Look-ahead        *    Host Protected Area feature set        *    WRITE_BUFFER command        *    READ_BUFFER command        *    NOP cmd        *    DOWNLOAD_MICROCODE        *    Advanced Power Management feature set             Power-Up In Standby feature set        *    SET_FEATURES required to spinup after power up             SET_MAX security extension        *    48-bit Address feature set        *    Device Configuration Overlay feature set        *    Mandatory FLUSH_CACHE        *    FLUSH_CACHE_EXT        *    SMART error logging        *    SMART self-test        *    General Purpose Logging feature set        *    WRITE_{DMA|MULTIPLE}_FUA_EXT        *    64-bit World wide name        *    IDLE_IMMEDIATE with UNLOAD        *    Write-Read-Verify feature set        *    WRITE_UNCORRECTABLE_EXT command        *    {READ,WRITE}_DMA_EXT_GPL commands        *    Segmented DOWNLOAD_MICROCODE        *    Gen1 signaling speed (1.5Gb/s)        *    Gen2 signaling speed (3.0Gb/s)        *    Native Command Queueing (NCQ)        *    Host-initiated interface power management        *    Phy event counters        *    Idle-Unload when NCQ is active             Device-initiated interface power management        *    Software settings preservation        *    SMART Command Transport (SCT) feature set        *    SCT Write Same (AC2)        *    SCT Features Control (AC4)        *    SCT Data Tables (AC5)             unknown 206[12] (vendor specific)        *    reserved 69[4]        *    reserved 69[7] Logical Unit WWN Device Identifier: 5000c5006a036439     NAA     : 5     IEEE OUI    : 000c50     Unique ID   : 06a036439 Checksum: correct How to Select Columns in Editors (Atom,Notepad++, Kate, VIM, Sublime, Textpad,etc) and IDEs (NetBeans, IntelliJ IDEA, Eclipse, Visual Studio, etc) I often hear people saying that "I am" is the shortest sentence in the English language.  I know that there are also discussions about sentences using the imperative mood such as "Go." that would be shorter, but my question is this:  Why would we (the people saying "I am" is a full sentence) not accept "I'm" as a complete sentence?  Is there some unwritten rule about contractions that says "I'm" wouldn't be correct? I am taking a course in Mathematical Methods for physicsPhysics (Junior Level).   We are working from   > Mathematical Methods for physicists, George B.Arfken .    I just need online resources covering ( Matrices, Determinants, Vector Analysis, Tensors and differential forms and Vector spaces...etc) to study and understand from. Does English have any singularia tantum besides mass nouns? and  are, respectively, nouns that have only a singular form and nouns that have only a plural form.  In English, we have a handful of pluralia tantum that are mass nouns which take the plural form (e.g. "riches" and "remains"), a whole load of pluralia tantum that refer to things that come in pairs (e.g. "trousers", "sunglasses", "knickers", or "scissors"), and at least one plurale tantum that fits into neither of the above categories ("clothes", meaning multiple items of clothing - it's clear what the hypothetical singular "clothe" would mean, yet it mysteriously isn't a word). Singularia tantum, on the other hand, seem less varied. As far as I can tell, they are all  - things like "information", "milk", and "racism".  One can imagine there being a singulare tantum that is not a mass noun. For example, we can imagine an alternate universe in which it is still correct English to talk about "a dog", but talking about "dogs" in the plural is incorrect and funny in the same way that it is incorrect and funny to talk about a "scissor". It might seem unintuitive to think that such a noun even could exist - surely, if it is not a mass noun, then people would just pluralise it with an "s" on the end like most other words? But the converse argument could just as well be made about countable pluralia tantum, and I still cannot go to a shop and buy a "clothe". Hence my question: do we have any such countable singularia tantum in the language? Have we in the past? When to delete your 0 vote answers? I've been in the SO community a little over a month now - and having a great time!  As I grow into a contributing citizen of stackoverflow, i'd like to ensure that i'm being responsible with my answers.   I've answered a few questions, some without upvotes, some voted on and some accepted.  I feel that after a certain period of time, 0 vote answers are probably providing more clutter than value.  Apparently, nobody has found them useful, so they probably aren't (or are poorly written). Tonight I went through and deleted my answers with 0 upvotes where some answer was accepted.  That was an easy decision.   I left my 0 vote answers where nothing was accepted yet, well, because I think they could provide the information that the OP requested.  But at some point, I think my answers might just be cluttering the issue.  So my question to you is: How do you know when it's time to delete your 0 vote answers?  Or even 1 vote answers for that matter?