I have found out that brightness can be controlled from a file /dev/class/backlight/intel_backlight/brightness. I am looking for a similar file from where I can change system volume ( sound ). I am not looking for a terminal command like given in the post at  but looking for the file that is changes by it (where it records the sounds info)  I am using Ubuntu 16.04, my laptop is hp-pavillion.
I have an external sound card which mostly works fine, except that when its first plugged in, or when I turn on my laptop, the volume gets set to 100%. That is, the overall system volume, as shown in the sound indicator.  What I'm looking for is a terminal command that will set that volume to 50%, so that I can run it on login and not have to worry that the first audio I play is going to blare out at me if I forget to turn the volume down. What commands allow you to change that volume, i.e. the one in the sound indicator?  I've poked around in gsettings and dbus, but have been unable to find anything that would let me set the system volume like that. I do know about alsamixer, but that's not the solution I'm looking for, since that doesn't allow me to change the volume using the sound indicator or my laptop's multimedia keys.
I was practicing with modeling a leaf using a image reference. Everything went fine and I finished modeling my leaf, but I wanted to make it more realistic (I'll add textures later), I saw lots of people using the Subdivision Surface modifier but it doesn't work for me.  My model:   My model when I add the Subdivision Surface modifier How to convert wstring into string? That car is way better than any car any of us have/has ever driven.      None of us know/knows which direction Ron's house is (in).    I have two questions here.   In both the cases, are we to use the singular verb, or the plural? In the end of the second sentence, is using the preposition where it's been used, necessary? Would it be okay if it had no prepositions in it? Is the Ratio of Associative Binary Operations to All Binary Operations on a Set of $n$ Elements Generally Small? I started thinking about the number of associative (binary) operations on a set with $n$ elements today.  Looking online I found  which indicates only $113$ of the possible $19,683$ operations on a three-element set satisfy association.  So, $50\%$ of binary operations on a two-element set satisfy association, and less than $0.6\%$ of all binary operations on a three element set satisfy association.  For an $n$-element set, where $n$ denotes a natural number, is the ratio $R_{n}=A_{n}/B_{n}$, of the number of associative binary operations $A_{n}$ to the number of all binary operations $B_{n}$, in general small?  I don't mean the following questions as equivalent, but since they seem more concretely answerable in principle, does   $$ \lim_{n \to +\infty} \frac{A_{n}}{B_{n}} = 0 ? $$       Also, is $F : n \to R_{n}$ a monotonically decreasing function?  Some Background of the Question: In his Linear Algebra Problem Book 1995 on p. 6 Paul Halmos writes "The commonly accepted attitudes toward the commutative law and the associative law are different.  Many real life operations fail to commute; the mathematical community has learned to live with that fact and even to enjoy it.  Violations of the associative law, on the other hand, are usually considered by specialists only."  For all I know, Halmos might only have written that to motivate the study of Linear Algebra and doesn't quite literally mean what he appears to say.  But, if he means what he appears to say, and if $F : n \to R_{n}$ is monotonically decreasing, or $R_{n}$ is generally small, I think there's something amiss with what Halmos says, since non-associative operations seem so common that one may as well enjoy them. Bounded in Probability and smaller order in probability I wanted to prove that if $X_n$ is bounded in probability and $Y_n = o_p(X_n)$, then $Y_n \rightarrow 0$ in probability   I  know the following definitions that is $X_n$ is bounded in probability meaning that   $P(|X_n|&lt;M)&gt;1-\epsilon$  and I know that $Y_n = o_p(X_n)$ implies that $Y_n/X_n \rightarrow0$ in probability Call to a member function on a non-object I'm looking to implement a phase lock in an FPGA without using any external components (other than the ADC). For simplicity locking to a simple binary pulse is adequate. The frequency of the signals is ~0.1-1% of the clock. I can't use the onboard clock PLL's because they are typically:   Not configurable (set during synthesis). Jittery. Don't support the frequency I need.   I've been sorting through the literature and found a few binary phase locked loops. Most notable a "pulse steal" design that I can post a link to if desired. I have implemented and synthesized with some success, but its jitter and lock range was not as good as advertised. I've also had success using a external DVCO, but I would prefer if I can implement everything on chip.  A digital circuit design or even a hint in the right direction would be helpful (I've been banging my head against this for a while), a proven FPGA implementation would be wonderful but not expected.   ADDED 10-27-2010   The actual DPLL design that I used has a "Random Walk Filter" as the loop filter (not the "pulse steal" described earlier, going through my notes that didn't work to well), which then drives the clock pulses to the DCO. The lock-in range is set via divider in the DCO. The sensitivity of the loop is established by varying the length of the random walk.   The paper in which this is found is cited at the end of this post. After implementing parts of it myself, I found that it was actually already implemented on OpenCores, however it turns out that in the last few months the project was deleted but I have the Verilog files saved if anyone wants them.  Yamamoto, H.; Mori, S.; , "Performance of Binary Quantized All Digital Phase-Locked Loop with a New Class of Sequential Filter," Communications, IEEE Transactions on , vol.26, no.1, pp. 35- 45, Jan 1978  doi: 10.1109/TCOM.1978.1093972  URL: I rooted my Dream/G1 last night and finally gave up on modding it (not for good mind you, but for the moment) and opted instead to just restore it to factory settings via Settings &gt; SD card &amp; phone storage &gt; Factory data reset, which did solve all the problems I was having with multitasking (and not being able to answer it, etc.)  Curiously, I still seem to have root on the phone, despite having reset it. I'd love to understand how that is possible! Superuser Permissions is the only non-stock app still on the phone, and I'm still able to use su to gain root privileges from adb shell. Is this because BusyBox installs to my SD Card?  My phone works just fine, so this is hardly critical, but the whole exercise was/is about knowing my phone better and this is most def. a mystery. Thanks! Create a hexadecimal colour based on a string with JavaScript Can I list-initialize a vector of move-only type? Do not give the impression that all votes are unanimously in favor of the winning close-reason. I closed for "belongs on superuser," yet SO claims I closed for a completely different reason.  Source: I did a fresh install of Ubuntu 16.04. /dev/md1 contains an ext4 filesystem that is mounted at /:  /dev/md1 on / type ext4 (rw,relatime,data=ordered)   Now I want to set the automatic filesystem check interval to one month, but I'm getting a strange error that I find no useful information about:  &gt; tune2fs -i 1m /dev/md1 tune2fs 1.42.13 (17-May-2015) tune2fs: Filesystem has unsupported read-only feature(s) while trying to open /dev/md1 Couldn't find valid filesystem superblock.   Rebooting didn't help. On another machine running Ubuntu 12.04, the same command works like a charm.  Does anyone have an idea what's wrong?  The command tune2fs -l /dev/md1 works fine, by the way. Here is its output:  tune2fs 1.42.13 (17-May-2015) Filesystem volume name:   &lt;none&gt; Last mounted on:          / Filesystem UUID:          38366a40-bbe1-476b-acfe-d271be6335eb Filesystem magic number:  0xEF53 Filesystem revision #:    1 (dynamic) Filesystem features:      has_journal ext_attr resize_inode dir_index filetype needs_recovery extent 64bit flex_bg sparse_super large_file huge_file dir_nlink extra_isize metadata_csum Filesystem flags:         signed_directory_hash Default mount options:    user_xattr acl Filesystem state:         clean Errors behavior:          Continue Filesystem OS type:       Linux Inode count:              8380416 Block count:              33521664 Reserved block count:     1676083 Free blocks:              32419430 Free inodes:              8312762 First block:              0 Block size:               4096 Fragment size:            4096 Group descriptor size:    64 Reserved GDT blocks:      1024 Blocks per group:         32768 Fragments per group:      32768 Inodes per group:         8192 Inode blocks per group:   512 Flex block group size:    16 Filesystem created:       Thu May 31 10:01:27 2018 Last mount time:          Thu May 31 10:49:41 2018 Last write time:          Thu May 31 10:15:14 2018 Mount count:              7 Maximum mount count:      -1 Last checked:             Thu May 31 10:01:27 2018 Check interval:           0 (&lt;none&gt;) Lifetime writes:          5782 MB Reserved blocks uid:      0 (user root) Reserved blocks gid:      0 (group root) First inode:              11 Inode size:               256 Required extra isize:     32 Desired extra isize:      32 Journal inode:            8 First orphan inode:       4325378 Default directory hash:   half_md4 Directory Hash Seed:      9d55d989-2c2b-4ad8-a29e-53c8798ec68e Journal backup:           inode blocks Checksum:                 0x3d9f8d23 Why are old initrd files of uninstalled kernels filling up /boot partition? Proof that the relation $5 \mid (a + 4b)$ is symmetric and transitive How to select top 10 records from each category Is there any way to debug bash script without using echo and logging?  I'm talking about using breakpoints and stuff like that. Other types of vector multiplication. As far as I've seen, there are only two types of vector multiplication defined, dot product/inner product which is defined in a vector space of any dimension, even infinite, and cross product, which is only defined in three dimensions. Are there more definitions of vector products? How to do version numbers? My company is building a product. It's going to be versioned by SVN. It's a webapp so basically there will never be a version out which doesn't have some features in them and thus could always be labeled as beta. But since it's going to be a corporate product I really don't want the "unstable watchout" on there. So how would you go about versioning? Is 1.0 stable? Should the build date be in the version number? Tell me what you guys think! Prove that $\frac{a_1^2}{a_1+a_2}+\frac{a_2^2}{a_2+a_3}+ \cdots \frac{a_n^2}{a_n+a_1} \geq \frac12$ Let $a_1, a_2, a_3, \dots , a_n$ be positive real numbers whose sum is $1$. Prove that $$\frac{a_1^2}{a_1+a_2}+\frac{a_2^2}{a_2+a_3}+ \ldots +\frac{a_n^2}{a_n+a_1} \geq \frac12\,.$$  I thought maybe the Cauchy and QM inequalities would be helpful. But I can't see how to apply it. Another thought (might be unhelpful) is that the sum of the denominators on the left hand side is $2$ (the denominator on the right hand side). I would really appreciate any hints. Why are these constructs using pre and post-increment undefined behavior?