Chirag's questions

I has a website hosted on CentOS VPS. That website has a self signed certificate.

Now,I migrated that site to another host. I generated keys for using sftp and ssh in old hosting.

The problem is that now I am unable to access the site from ubuntu. Whereas it is accessible from other computers.

I tried various browsers (firefox, google-chrome, chromium) but I cant open the site. Deleting the cache also didn't change things.

Any clue?

This is what happens in chromium:

UPDATE: I ran ssh-keygen -R hostname that didn't help. Finally I deleted known_hosts file as well, still not working.

Uninstalling and re-installing the browser didn't solve the issue.

Logging out as guest user also didn't open the page.

I generated DSA key using ubuntu. Saved the public key on remote server, such that keys are required before connecting ssh.

I have forgot the passphrase for that key. How can I retrieve it?

How to encrypt the connection with server using filezilla in Linux? I read, it is possible in Windows using Putty. Just wondering how to do it in Ubuntu?

With android and Google Play becoming so popular, it would be great to have Ubuntu on mobile devices again.

Some archaic references:

http://blog.canonical.com/2008/06/24/ubuntu-mid-edition-804-achieves-its-first-public-release/

https://wiki.ubuntu.com/MobileTeam/Mobile?action=show&redirect=MobileAndEmbedded

I am using VLC media player on Ubuntu 12.04. A few videos having high bit-rate play sound very loudly. To an extent I feel that it may affect my speakers.

Some references:

https://superuser.com/a/337277/152615

http://www.tomshardware.com/forum/80989-35-does-media-player-damage-speakers

What should I do to keep sound to an optimum? If I lower the system volume. For few videos, I need to increase the sound to make it audible.

Is there a way to keep sound to a fixed level, irrespective of video or audio quality (or bit-rate)?

I am trying to change the icon for .py file.

I referred:

https://askubuntu.com/a/78645/78407

https://askubuntu.com/a/56725/78407

and

https://help.ubuntu.com/community/AddingMimeTypes

Still no success in changing the icon of python scripts. They remain like gedit icons.

I am using ubuntu 12.04. I have a .mp4 video for which I want to change default media player to vlc.

When I try to go to properties by right clicking on that video.

I get the following message. How to overcome this.

Output of mediainfo filename.mp4

General
Complete name                            : Interview with MIT Physics Professor Walter Lewin.mp4
Format                                   : MPEG-4
Format profile                           : Base Media / Version 2
Codec ID                                 : mp42
File size                                : 10.7 MiB
Duration                                 : 3mn 41s
Overall bit rate mode                    : Variable
Overall bit rate                         : 407 Kbps
Encoded date                             : UTC 2008-10-16 15:15:29
Tagged date                              : UTC 2008-10-16 15:15:29
gsst                                     : 0
gstd                                     : 221656
gssd                                     : B4A7D0A24HH1345230487367165
gshh                                     : o-o---preferred---hkg05s03---v14---lscache4.c.youtube.com

Video
ID                                       : 2
Format                                   : AVC
Format/Info                              : Advanced Video Codec
Format profile                           : [email protected]
Format settings, CABAC                   : No
Format settings, ReFrames                : 1 frame
Codec ID                                 : avc1
Codec ID/Info                            : Advanced Video Coding
Duration                                 : 3mn 41s
Bit rate                                 : 280 Kbps
Maximum bit rate                         : 997 Kbps
Width                                    : 352 pixels
Height                                   : 288 pixels
Display aspect ratio                     : 1.222
Frame rate mode                          : Constant
Frame rate                               : 29.970 fps
Standard                                 : PAL
Color space                              : YUV
Chroma subsampling                       : 4:2:0
Bit depth                                : 8 bits
Scan type                                : Progressive
Bits/(Pixel*Frame)                       : 0.092
Stream size                              : 7.37 MiB (69%)
Title                                    : (C) 2007 Google Inc. v08.13.2007.
Encoded date                             : UTC 2008-10-16 15:15:29
Tagged date                              : UTC 2008-10-16 15:15:29

Audio
ID                                       : 1
Format                                   : AAC
Format/Info                              : Advanced Audio Codec
Format profile                           : LC
Codec ID                                 : 40
Duration                                 : 3mn 41s
Bit rate mode                            : Variable
Bit rate                                 : 125 Kbps
Maximum bit rate                         : 280 Kbps
Channel(s)                               : 2 channels
Channel positions                        : Front: L R
Sampling rate                            : 44.1 KHz
Compression mode                         : Lossy
Stream size                              : 3.30 MiB (31%)
Title                                    : (C) 2007 Google Inc. v08.13.2007.
Encoded date                             : UTC 2008-10-16 15:15:29
Tagged date                              : UTC 2008-10-16 15:15:29

To begin with, I have already read the following solutions:

Cannot Update Java plugin for Google Chrome

How do I get Java plugin for Chrome?

Installing Chrome Java Plugin

How to install Oracle Java web plugin on Chrome in 12.04?

and I hope this does not get marked as duplicate. I previously un-installed OpenJDK and IceTea plugin and installed java-sdk 7 update 4. I made a symbolic link to libnpjp.so in my installation folder to ~/.mozilla/plugins. Everything (including Chrome) was running smoothly as it should have.

Today, when I installed java-sdk 7 update 5, I followed same steps as before but now, I get to see this:

and this:

I even un-installed and reinstalled chrome, but could not help.

I am running Ubuntu 12.04, Chrome Version 21.0.1180.79.

This is really most annoying experience so far.

PS: Kindly don't tell to reinstall Java using some PPA.

Few commands that need to do sudo remind you that "You do not have the privilege" or "Are you root?" etc.

while a few commands do not give such message. For example, if you do fdisk -l instead of sudo fdisk -l ubuntu does not give any message. This is particularly confusing for people who come from different linux distro (eg: CentOS, RHEL etc.).

Wouldn't it be a good idea to notify user each time he commits such mistake, that he/she must be a sudoer to execute that particular command.

When I do fdisk -l in terminal there is no output? What can be the probable reason? How to fix it?

I have two my hard disk divided into two partition (apart from swap). First one is /dev/sda3 on which I have my ubuntu installation. Second one is /dev/sda1. Now, when I try to copy a file to /dev/sda1, I need to do a sudo, because my user does not have permission.

How do I give read, write permission to my user? I know chmod 777 is a bad idea. How about chown or chgrp?

by the way, /dev/sda1 is mounted as /media/hood, so what should be the syntax my command?

I have two my hard disk divided into two partition (apart from swap). First one is /dev/sda3 on which I have my ubuntu installation. Second one is /dev/sda1. Now, when I try to copy a file to /dev/sda1, I need to do a sudo, because my user does not have permission.

How do I give read, write permission to my user? I know chmod 777 is a bad idea. How about chown or chgrp?

The output of mount command is as as follows:

/dev/sda3 on / type ext4 (rw,errors=remount-ro)
proc on /proc type proc (rw,noexec,nosuid,nodev)
sysfs on /sys type sysfs (rw,noexec,nosuid,nodev)
none on /sys/fs/fuse/connections type fusectl (rw)
none on /sys/kernel/debug type debugfs (rw)
none on /sys/kernel/security type securityfs (rw)
udev on /dev type devtmpfs (rw,mode=0755)
devpts on /dev/pts type devp
ts (rw,noexec,nosuid,gid=5,mode=0620)
tmpfs on /run type tmpfs (rw,noexec,nosuid,size=10%,mode=0755)
none on /run/lock type tmpfs (rw,noexec,nosuid,nodev,size=5242880)
none on /run/shm type tmpfs (rw,nosuid,nodev)
gvfs-fuse-daemon on /home/chirag/.gvfs type fuse.gvfs-fuse-daemon (rw,nosuid,nodev,user=chirag)

/dev/sda1 on /media/hood type ext4 (rw,nosuid,nodev,uhelper=udisks)

I am using terminator 0.96 as terminal emulator. How can I make it run in the background and make it appear/disappear like guake terminal (i.e. using a shortcut key).

I use firefox & as command in terminal. This must dissociate firefox from terminal. Still when I close terminal, firefox exits. Any ideas, why this happens? How can I overcome this situation?

Shutter is a nice software but it takes a while to load. I observed that initially it loads some plugins (eg:upload-plugin). Is there a way to disable these plugins so that shutter loads quickly?

please illustrate how to do this.

I prefer using alsa only while I make screencast and do skype. Other times, I use pulseaudio/alsa. Is there a quick and easy way to switch between these two states on Ubuntu 12.04 desktop?

I am not able to uncompress a file with .tar.gz extension

Did sudo tar -xvzf ~/Downloads/file.tar.gz /opt/ but no success. it says:

tar: /opt: Not found in archive
tar: Exiting with failure status due to previous errors

Using CompizConfiguration Settings Manager (CCSM), I've assigned hold Super + Roll mouse button to zoom in/out.

When I hold Super key it by default shows shortcut list on Ubuntu 12.04. I want these two process (e.g. zoom in and appearance of the shortcut list) not to occur simultaneously.

I did not find any useful tip on Google.

I want to create some screencast, I am using avconv (recent ffmpeg counterpart) for doing so.

This is the reference for command I used. I also referred the avconv manual pages. Due to some reason I am unable to record audio from microphone into the screencast.

What is the -f switch for audio from microphone? I tried -f jack but it gives an error message.

I am not sure whether the microphone audio drivers are installed on my PC. Command I used is as follows:

avconv -f x11grab -f jack -s hd1080 -r 30 -i 0:0  screencast.mov

Error message I get is:

Cannot connect to server socket err = No such file or directory
Cannot connect to server socket
exec of JACK server (command = "/usr/bin/jackd") failed: No such file or directory
jack server is not running or cannot be started
[jack @ 0x9b6dc80] Unable to register as a JACK client
0:0: Input/output error

How can I see using command-line whether I am connected to network using eth0, eth1 or wln0 etc?

Well, to elaborate, I have a desktop sidebar which I installed using program "conky". This sidebar has meter that shows internet speed. Since I am not using eth0, I need to make a minor change in ~/.conkyrc file. I need to replace "eth0" with whatever network is being used by my wireless card to connect to internet (via a router).

http://ubuntuforums.org/showthread.php?t=249889

In the above link it is shown that I need to do

sudo apt-get install nfs-kernel-server nfs-common portmap

However a software called portmap doesnot exist in ubuntu 12.04

How exactly do I configure NFS in ubuntu 12.04?