I have installed Eclipse Oxygen;when I type   export PATH=$PATH:/home/ivan/java-oxygen/eclipse   in the bash, I can launch eclipse from bash from any location, however, no matter whether I add  PATH=$PATH:/home/ivan/java-oxygen/eclipse   or  export PATH=$PATH:/home/ivan/java-oxygen/eclipse   to /.bashrc or /etc/bash.bashrc, I cannot launch Eclipse without typing   export PATH=$PATH:/home/ivan/java-oxygen/eclipse   every time I launch the new bash.
I found the .bashrc file and I want to know the purpose/function of it. Also how and when is it used?
What is this "forbidden" icon in my systray? The following is a systray applet icon that appeared in my Unity session after I upgraded to Ubuntu 16.10. Its menu is tall, narrow and empty. What is it? A real nxn matrix always has a real eigenvalue when n is odd what do it mean by "A real nxn matrix always has a real eigenvalue when n is odd?" Shouldnt it be that regardless of odd or even there will always have a real root?  hope to hear from you guys soon:) It seems Microsoft has tried to solve this problem .  In Windows 7, there is no boundary between monitors and the mouse can move freely across the top of the screen between my 3 monitors, provided I had set their heights equal in display settings. Windows 8 introduced sticky corners. See .  Windows 10 got sticky corners as well. There are a few pixels at the top corners of each display where the mouse cannot cross over onto the other display. One must move the cursor down to avoid this region in order to get to the next display.  The image shows roughly the region where mouse movement is not permitted in Windows 10, but is allowed in Windows 7.    Personally, I had no problem with unrestricted mouse movement across the top of my screens - I got used to "aiming" for the x, and the convenience of unrestricted cursor movement. Like all the people who wanted to disable it in W8, I'm wondering if there is a way to disable it in W10.  Edit to address possible duplicate:  Although the problem is identical to the one in , solutions to solve the problem in W8 involving editing the registry key MouseCornerClipLength do not work in W10, since that registry key is not present in W10. Also adding that key and setting the value doesn't work. I searched the entire registry and couldn't find it in another location. No other W10 keys in the node referenced in the W8 solution are obvious replacements.  Edit to address possible solutions in comments  harrymc's  and  that worked for for Windows 8.1 do not work in Windows 10. How can I control a servo motor with the PWM output of a microcontroller? I wanted to control the direction of servo motor with a switch. I am using an Atmega32.  Outputs are PIND4 and PIND5 and the input is PINA3, but the two servo motors turn only in 1 direction.  #ifndef F_CPU  #define F_CPU 1000000UL   #endif  #include &lt;avr/io.h&gt; #include &lt;util/delay.h&gt; #include &lt;avr/interrupt.h&gt;   int main(void) { DDRD= 0xFF ; DDRA=0x00; PORTA =0x00; // FAST PWM TCCR1A |= 1&lt;&lt;COM1A0 | 1&lt;&lt;COM1A1 | 1&lt;&lt;WGM11 |1&lt;&lt;COM1B0|1&lt;&lt;COM1B1 ; TCCR1B= 1&lt;&lt;WGM12|1&lt;&lt;WGM13 ; ICR1 = 19999 ;  TCCR1B |=1&lt;&lt;CS10 ; while (1) {    if(PORTA==0x08) //if pina3 is 1    {     OCR1A = ICR1 -2000 ;   //turn servo 1     _delay_ms(1000);          OCR1B=ICR1-2000;    //turn servo 2     _delay_ms(1000);     }     if(PORTA==0x00)// if pina3 is 0     {       OCR1A = ICR1 -900 ; //turn servo 1 in the other direction       _delay_ms(1000);               OCR1B=ICR1-900;     //turn servo 2 in the other direction       _delay_ms(1000);      } }       return 0 ;  } I could have modifications ready for a specific question that was downvoted. I felt like the best thing to do was to delete the post first.  Is it possible to flag for moderator attention after you deleted the post ? Why might right aligned field labels be better? For the longest time, I've used left-aligned labels in my forms, like this:    I did this because I thought having the labels left aligned made it easier for readers to scan the list of labels.  However, I found my axiom challenged recently while watching  from , in which Billy asserts that right-aligned labels are simply better, like this:    I've done a bunch of research and found a lot of discussion, including , which compares and contrasts the approaches, but nothing definitive.  In particular, I haven't been able to find anything to indicate why Billy Hollis changed his opinion from left- to right- alignment for labels (apparently he switched around 2007).   I figure Billy's too smart to have made the change without evidence - so I'm interested in seeing that evidence for myself. Prove $\sum_{d \leq x} \mu(d)\left\lfloor \frac xd \right\rfloor = 1 $ Can I disable auto logon on windows 10 home I recently setup a new computer for my parents with windows 10 home. I made two local accounts for them - no microsoft accounts. I also would like to keep them without a password. Problem is now that windows automatically signs in with the last used account. No lock/login screen.  I tried a number of answers from similar questions here but none worked. Since it's a home version there are no group policies and the method using task scheduler does not work because accounts with no password are not allowed to create such tasks.  Are there other options to force windows to show a user list on startup without setting passwords for the accounts? What's the best practice of inserting a collection of data into a SQL Server database Optimization when Cost Function Slow to Evaluate Aligning three figures next to each other based on text width Problem:  I am trying to align three figures next to each other with text centered to each figure. This is going well until the box for the third box does not adjust after the text width.  Minimal Working Example (MWE):  \documentclass{article} \usepackage{graphicx} \usepackage{caption}  \begin{document}  \begin{figure}[!tbp]   \centering   \begin{minipage}[b]{0.2\textwidth}     \includegraphics[width=\textwidth]{icon-password.eps}     \caption*{Login system}   \end{minipage}   \hfill   \begin{minipage}[b]{0.2\textwidth}     \includegraphics[width=\textwidth]{icon-shopping.eps}     \caption*{Shopping cart}   \end{minipage}   \hfill   \begin{minipage}[b]{0.2\textwidth}     \includegraphics[width=\textwidth]{icon-clock.eps}     \caption*{Temporary information}   \end{minipage} \end{figure}  \end{document}   Outputs:   Desired outcome:  To get the width to adjust after the text so that "Temporary information" can be written out in one line instead of two. How do I select an object in the 3D viewport? "sudo -u postgres psql postgres" does not ask for password How do I add this extra partition to my installed Ubuntu system? I started installing Ubuntu by watching a video tutorial about doing a disk partition installation, for that, inside Windows' 7 own disk partitioning tool. After a defrag I cut 100GB that I pretended to use on my Ubuntu installation for a little try out, now, while installing, I never really chose where I wanted Ubuntu to be installed, so I guess it just made a partition by itself of the minimum that the installation tells you it needs.  How can I now give the other 92 GB I had left apart only for that task?  Here's what my partitions look like now.     Here's a df:    And here's the GParted tool un ubuntu: What is IEEE 802.3 Ethernet's communication type: Synchronous or Asynchronous? In the IEEE 802.3 frame structure there is a 7 byte preamble section for synchronization. If it is really for synchronization does that mean Ethernet is synchronous and not asynchronous?    Ethernet structure for reference: Objects not rotating with each other (Rubik's cube) What is the most CPU efficient way to ensure that NumLock is on? Situation: I have a script watching over NumLock status, well not really watching, but turning it On every 1 second. The script is running in the background.  Reasoning: I often accidentally turn off NumLock. And I have no indicator of NumLock status on the keyboard.  OS, DE, DM, WM, xmodmap:  :  $ lsb_release -a  No LSB modules are available. Distributor ID: LinuxMint Description:    Linux Mint 18 Sarah Release:    18 Codename:   sarah   :  echo $DESKTOP_SESSION  cinnamon   :  cat /etc/X11/default-display-manager  /usr/sbin/mdm   :  wmctrl -m | head -n 1  Name: Mutter (Muffin)   :  xmodmap -pm  xmodmap:  up to 4 keys per modifier, (keycodes in parentheses):  shift       Shift_L (0x32),  Shift_R (0x3e) lock        Caps_Lock (0x42) control     Control_L (0x25),  Control_R (0x69) mod1        Alt_L (0x40),  Alt_R (0x6c),  Meta_L (0xcd) mod2        Num_Lock (0x4d) mod3       mod4        Super_L (0x85),  Super_R (0x86),  Super_L (0xce),  Hyper_L (0xcf) mod5        ISO_Level3_Shift (0x5c),  Mode_switch (0xcb)   My original Bash script follows:  #!/bin/bash  while true do    numlockx on    sleep 1s  done   As you can see, the script does not care about current status of NumLock. It just keeps turning it on.  Goal: I would like to make the script at least somewhat CPU efficient.  Question: What is the most CPU efficient way to ensure that NumLock is On in Linux (Mint 18)? I'm no expert in darkroom photography, but it seems a little odd that there is a type of light that doesn't affect film or developing paper etc. The only way that I could think to explain it is:   The low frequency red photons don't have enough energy to raise electron states in the film/paper, or Magic   either way, I'm curious to know how this handy tool is, as per title, safe. How do I loop through or enumerate a JavaScript object? I need to convert one into 1, two into 2 and so on.  Is there a way to do this with a library or a class or anything?