Rahul Virpara's questions

I recently installed Ubuntu Mate 18.04 on my old laptop. It has 3 GB of RAM and Intel Core2Duo processor.

It takes long time to get to the login screen and more waiting to get to the desktop after entering password.

I have boot screen disabled using GRUB_CMDLINE_LINUX_DEFAULT="" by changing the file /etc/default/grub.

I have tried everything described in the answers here but no luck so far !

/dev/sda3 is the partition where Ubuntu is installed. The benchmark of this partition gives average read rate 44.9 MB/s and average access time 13.28 msec, so it is not an issue with the HDD.

Output from systemd-analyze blame,

     45.669s dev-sda3.device
     33.585s systemd-journal-flush.service
     25.686s apt-daily.service
     21.490s systemd-tmpfiles-setup-dev.service
     13.915s loadcpufreq.service
     11.823s grub-common.service
     11.094s apparmor.service
     10.979s snapd.seeded.service
     10.867s networking.service
     10.325s speech-dispatcher.service
      9.986s networkd-dispatcher.service
      9.931s rsyslog.service
      9.931s gpu-manager.service
      9.930s pppd-dns.service
      9.900s apport.service
      9.480s alsa-restore.service
      9.463s lm-sensors.service
      8.987s bluetooth.service
      8.987s thermald.service
      8.951s avahi-daemon.service
      8.250s dev-loop7.device
      7.847s dev-loop10.device
      7.808s dev-loop9.device

Output from systemd-analyze time,

Startup finished in 1min 39.563s (kernel) + 1min 26.728s (userspace) = 3min 6.292s graphical.target reached after 1min 663ms in userspace

Output from systemd-analyze critical-chain,

The time after the unit is active or started is printed after the "@" character.
The time the unit takes to start is printed after the "+" character.

graphical.target @1min 663ms
└─multi-user.target @1min 662ms
  └─snapd.seeded.service @49.682s +10.979s
    └─snapd.service @1min 400ms +253ms
      └─basic.target @39.421s
        └─sockets.target @39.419s
          └─snapd.socket @39.188s +228ms
            └─sysinit.target @39.183s
              └─systemd-timesyncd.service @38.808s +371ms
                └─systemd-tmpfiles-setup.service @38.564s +174ms
                  └─systemd-journal-flush.service @4.970s +33.585s
                    └─systemd-journald.service @4.128s +837ms
                      └─systemd-journald-dev-log.socket @4.122s
                        └─system.slice @3.927s
                          └─-.slice @3.863s

Is there any functionality like lens for Gnome shell? or any modified version of Gnome Shell.

I use a python script to set brightness to zero.

#!/usr/bin/python

import dbus 
bus = dbus.SessionBus() 
proxy = bus.get_object('org.gnome.SettingsDaemon',
                       '/org/gnome/SettingsDaemon/Power') 
iface = dbus.Interface(proxy,dbus_interface='org.gnome.SettingsDaemon.Power.Screen')
iface.SetPercentage(0)

I've put it in Startup Applications. It works only when I login. There is full brightness at login screen.

Where should I put this so that it sets brightness to zero at login screen?

I want to redirect some sites to localhost. I can use hosts file which resides in directory C:\WINDOWS\system32\drivers\etc in windows.

Which is equivalent of this file in Ubuntu?

gnome-appearance-properties is no more available in Gnome3 and newer.

I want to change Background and Text colors of Windows, Input Boxes, Selected Items, etc. and customize Theme.

Is there any application available to do that?

I've bunch of folders in folder A. I want to move files from all those folders to A.

Or

I want to cut all files from child folders and paste them in parent folder.

How to do that?

first of all, I want to create shell script to start/stop downloads in torrent client. I don't need CLI but if you know how I can do that with CLI using shell script then it is okay.

I use jDownloader which is GUI based application but has some command line arguments as below which I use to start/stop download.

-h/--help       Show this help message
-a/--add-link(s)    Add links
-co/--add-container(s)  Add containers
-d/--start-download Start download
-D/--stop-download  Stop download
-H/--hide       Don't open Linkgrabber when adding Links
-m/--minimize       Minimize download window
-f/--focus      Get jD to foreground/focus
-s/--show       Show JAC prepared captchas
-t/--train      Train a JAC method
-r/--reconnect      Perform a Reconnect
-C/--captcha <filepath or url> <method> Get code from image using JAntiCaptcha
-p/--add-password(s)    Add passwords
-n --new-instance   Force new instance if another jD is running

So I can easily start/stop download as follows,

jdownloader --start-download
jdownloader --stop-download

now I want torrent client to do that through shell script.

I found that it can be done with loopback as follows

menuentry "Lucid ISO" {
loopback loop (hd0,1)/boot/iso/ubuntu-10.04-desktop-i386.iso
linux (loop)/casper/vmlinuz boot=casper iso-scan/filename=/boot/iso/ubuntu-10.04-desktop-i386.iso noprompt noeject
initrd (loop)/casper/initrd.lz
}

But it works only with ubuntu or its derivatives. How it should be written if I want to boot other live images like fedora, cent, opensuse etc. ?

Edit: I found some other entries but all of them are probably debian based.

menuentry "Linux Mint 10 Gnome ISO" {
 loopback loop /linuxmint10.iso
 linux (loop)/casper/vmlinuz file=/cdrom/preseed/mint.seed boot=casper initrd=/casper/initrd.lz iso-scan/filename=/linuxmint10.iso noeject noprompt splash --
 initrd (loop)/casper/initrd.lz
}

menuentry "DBAN ISO" {
 loopback loop /dban.iso
 linux (loop)/DBAN.BZI nuke="dwipe" iso-scan/filename=/dban.iso silent --
}


menuentry "Tinycore ISO" {
 loopback loop /tinycore.iso
 linux (loop)/boot/bzImage --
 initrd (loop)/boot/tinycore.gz
}


menuentry "SystemRescueCd" {
 loopback loop /systemrescuecd.iso
 linux (loop)/isolinux/rescuecd isoloop=/systemrescuecd.iso setkmap=us docache dostartx
 initrd (loop)/isolinux/initram.igz
}

Edit2: How to chainload grub and syslinux from grub2?

Edit3: I want to boot other live images without any removable devices and use grub2 so need menu entries specific to grub2.

if I write,

#!/bin/bash
echo "foo"

or

#!/bin/sh
echo "foo"

both yields same. I have seen some scripts starting with #!/bin/sh or #!/bin/bash. Is there any difference between them?

Whenever I issue command sudo apt-get install foo it does not ask for password. is it because of user groups?

How to make it prompt for password?

Edit: My sudoers file

apple@Ascension:~$ sudo cat /etc/sudoers
#
# This file MUST be edited with the 'visudo' command as root.
#
# Please consider adding local content in /etc/sudoers.d/ instead of
# directly modifying this file.
#
# See the man page for details on how to write a sudoers file.
#
Defaults    env_reset

# Host alias specification

# User alias specification

# Cmnd alias specification

# User privilege specification
root    ALL=(ALL:ALL) ALL

# Members of the admin group may gain root privileges
%admin ALL=(ALL) ALL

# Allow members of group sudo to execute any command
%sudo   ALL=(ALL:ALL) ALL

#includedir /etc/sudoers.d
ALL ALL=(ALL) NOPASSWD:ALL
ALL ALL=(ALL) NOPASSWD:ALL
ALL ALL=(ALL) NOPASSWD:ALL

I need to stop/start download through shell script in Azureus(Vuze). I know there is CLI and I can invoke it as

java -jar Azureus2-XXX.jar --ui=console

The ? will show a list of commands I can use. To get a list of torrents,

show torrents

etc. But it is CLI. I need shell script to do that so How I can use it to stop/start downloads through shell script?

Is there any way to do that?

I use ZTE USB Modem on Natty Narwhal. Every thing works fine but sometimes it get disconnected. I want to write Shell script that reconnects mobile broadband if it is disconnected or the received data is less than 20 KB after 5 seconds of connection.

So my question is how to enable/disable mobile broadband? How to check for data received? and how to enable/disable network service ?

note: terminal commands only Or if you can write script, I'll be very thankful.

I Downloaded Vuze from official site as tar.bz2 file. Set up JRE. Now if I try to execute it says

Starting Azureus...
Suitable java version found [java = 1.6.0_31]
Configuring environment...
Java exec found in PATH. Verifying...
Browser check failed with: Cannot load 64-bit SWT libraries on 32-bit JVM
Auto-scanning for GRE/XULRunner.  You can skip this by appending the GRE path to LD_LIBRARY_PATH and setting MOZILLA_FIVE_HOME.
  checking /usr/lib/firefox-11.0 for GRE
GRE found at /usr/lib/firefox-11.0.
Browser check failed with: Could not initialize class org.eclipse.swt.widgets.Display
Can't create browser.  Will try to set LD_LIBRARY_PATH and hope Vuze has better luck.
setting LD_LIBRARY_PATH to: /usr/lib/firefox-11.0
setting MOZILLA_FIVE_HOME to: /usr/lib/firefox-11.0
Loading Azureus:
java -Xmx128m -cp "./Azureus2.jar:./swt.jar" -Djava.library.path="/home/apple/Downloads/azureus" -Dazureus.install.path="/home/apple/Downloads/azureus" -Dazureus.script="./azureus" -Dazureus.script.version=2 org.gudy.azureus2.ui.swt.Main 
file:/home/apple/Downloads/azureus/Azureus2.jar ; file:/home/apple/Downloads/azureus/swt.jar ; file:/home/apple/Downloads/azureus/
changeLocale: *Default Language* != English (India). Searching without country..
changeLocale: Searching for language English in *any* country..
changeLocale: no message properties for Locale 'English (India)' (en_IN), using 'English (default)'
java.lang.reflect.InvocationTargetException
    at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
    at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:39)
    at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:27)
    at java.lang.reflect.Constructor.newInstance(Constructor.java:513)
    at org.gudy.azureus2.ui.swt.Main.<init>(Main.java:114)
    at org.gudy.azureus2.ui.swt.Main.main(Main.java:292)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
    at java.lang.reflect.Method.invoke(Method.java:597)
    at com.aelitis.azureus.launcher.MainExecutor$1.run(MainExecutor.java:37)
    at java.lang.Thread.run(Thread.java:662)
Caused by: java.lang.UnsatisfiedLinkError: Cannot load 64-bit SWT libraries on 32-bit JVM
    at org.eclipse.swt.internal.Library.loadLibrary(Library.java:214)
    at org.eclipse.swt.internal.Library.loadLibrary(Library.java:194)
    at org.eclipse.swt.internal.C.<clinit>(C.java:21)
    at org.eclipse.swt.internal.Converter.wcsToMbcs(Converter.java:63)
    at org.eclipse.swt.internal.Converter.wcsToMbcs(Converter.java:54)
    at org.eclipse.swt.widgets.Display.<clinit>(Display.java:132)
    at org.gudy.azureus2.ui.swt.mainwindow.SWTThread.<init>(SWTThread.java:84)
    at org.gudy.azureus2.ui.swt.mainwindow.SWTThread.createInstance(SWTThread.java:63)
    at com.aelitis.azureus.ui.swt.Initializer.<init>(Initializer.java:162)
    ... 12 more
Exit from Azureus complete
No shutdown tasks to do
Azureus TERMINATED.

Is it caused by SWT.jar? How to get rid from this?

I use ubuntu 11.04 Natty Narwhal. I was searching for download manager and I found Gwget Download Manager as highly recommended Download Manager for ubuntu. I have installed it from Software Center which is 1.0.4. Now the problem is I can only run this one time if I close Gwget and try to run it again it never shows up. If I logout and try after logging in again I can run it for the first time then it does not start. How do I get rid of this problem?

Possible Duplicate:
Adding swap partition after system installation

i have already installed ubuntu 11.04 without any swap partition. Now i want to create swap partition which should be utilized by this os. i have tried creating one by partitioning but ubuntu can not use this swap memory and swap usage remains unused. please tell me how to make it usable by ubuntu.