Ali Razmdideh's questions

I'm setting up a loop device for VM raw image back-file, with this command:

sudo losetup /dev/loop0 "/home/asus/VirtualBox VMs/Windows RAW/Windows 10.img" 

And it works fine.

$ losetup -l
NAME       SIZELIMIT OFFSET AUTOCLEAR RO BACK-FILE                                            DIO LOG-SEC
/dev/loop0         0      0         0  0 /home/asus/VirtualBox VMs/Windows RAW/Windows 10.img   0     512

But I want to make this change permanent, so I created this .sevice to run at startup:

$ cat /etc/systemd/system/loops-setup.service
[Unit]
Description=Setup loop devices
DefaultDependencies=no
Conflicts=umount.target
Before=local-fs.target
After=systemd-udev-settle.service
Required=systemd-udev-settle.service

[Service]
Type=oneshot
ExecStart=/sbin/losetup /dev/loop0 "/home/asus/VirtualBox VMs/Windows RAW/Windows 10.img"
ExecStop=/sbin/losetup -d /dev/loop0
TimeoutSec=60
RemainAfterExit=yes

[Install]
WantedBy=local-fs.target
Also=systemd-udev-settle.service

Also this service starts well manually:

sudo systemctl start loops-setup

But it failed to start at startup, and shows this error:

May 11 19:57:17 ubuntu losetup[308]: losetup: /dev/loop0: failed to set up loop device: No such file or directory

I guess its because of hierarchy of services, and I should change Before and After options but I don't know how to do this.

Thanks in advance.

New nautilus is not using file-roller any more by default, it has switched to its native expression, but I want to use file-roller on right click.

I found this answer, which worked in Ubuntu 17.10. But nautilus-actions package is not yet Ubuntu 18.04's official repositories.

So is there any other method for this purpose?

I'm trying to add underline between two word in Persian.

In English , shift + - combination works well and I can type underline character well, like this:

Ask_Ubuntu

But in Persian this keys combination not work. And when I press shift + - instead of underline typing, the letters stretch like this:

اسکـاوبونتو

So, how can I use underline in Persian language?

I want to install telegram-cli in Ubuntu 17.04 AMD64. So I use this commands:

sudo snap install telegram-cli

But it not support Persian/Arabic letters. All Persian/Arabic letters has been messed up. And I can't type any Persian/Arabic characters.

And here is the question, How can I solve this problem.

As far as I know, ping send ICMP echo request to host. And ICMP is the layer 3 of OSI model.

But TOR use TCP , which is the layer 4 of OSI model.

So ping can't be run through TOR normally.

But here is the question, How can I run ping requests through TOR by force. Is it possible?

I'm using Ubuntu 17.10 and I want to install OpenCV 3 on it.

How can I install OpenCV for Python 3 on Ubuntu 17.10?

I've installed opencv for Anaconda with this command:

conda install opencv

And when I run python3.6 in terminal , I can import cv2 module with any issue.

So opencv has been installed for Anaconda's path successfully.

Python 3.6.1 |Anaconda custom (64-bit)| (default, May 11 2017, 13:09:58) 
[GCC 4.4.7 20120313 (Red Hat 4.4.7-1)] on linux
Type "help", "copyright", "credits" or "license" for more information.
>>> import cv2

But when I import cv2 in python3.5:

Python 3.5.3 (default, Jan 19 2017, 14:11:04) 
[GCC 6.3.0 20170118] on linux
Type "help", "copyright", "credits" or "license" for more information.
>>> import cv2
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
ImportError: No module named 'cv2'

So I can't use opencv in system's python.

And here is the question; how to can I import Anaconda's modules (especially cv2) in system's python?

How to create symbolic link from Anaconda's modules to system's python path?

I want to type a character in a shell and have xdotool send that character's signal to gedit, so that character will be typed in gedit.

I have written this script:

#!/bin/bash
gedit -s &
GEDPID=$!
sleep 2s
GEDWINID=`xdotool search --pid $GEDPID | tail -1`
echo "press any keys"
read i
xdotool windowactivate --sync $GEDWINID key --clearmodifiers --delay 100 "$i" && wmctrl -a Terminal

Everything works well except that the script waits for enter to send a keyboard signal to gedit.

So I've changed read i to read -n1 i, to make the script do its job without enter.

#!/bin/bash
gedit -s &
GEDPID=$!
sleep 2s
GEDWINID=`xdotool search --pid $GEDPID | tail -1`
echo "press any keys"
read -n1 i
xdotool windowactivate --sync $GEDWINID key --clearmodifiers --delay 100 "$i" && wmctrl -a Terminal

But it doesn't type any characters in gedit!

And here is the question, what is the second script's issue? What's difference between read i and read -n1 i that causes this problem?

I have recently upgrade my Xubuntu from 16.10 to 17.04.

Every things works well except systemd-resolve. some times it makes cpu usage too high and I don't know why this issue has been happend.

And here is the top command output:

  PID USER      PR  NI    VIRT    RES    SHR S  %CPU %MEM     TIME+ COMMAND                               
  1114 systemd+  20   0   51532   6744   4504 R   100  0.0   9:51.67 systemd-resolve                       
  1152 dnsmasq   20   0   64360   2892   2480 R  38.9  0.0   4:05.53 dnsmasq                               
  1245 root      20   0  376644  89644  64436 S   1.7  0.5   0:35.69 Xorg                                  
  1624 asus      20   0  370160  45820  28488 S   0.7  0.3   0:00.90 python2                               
  2238 asus      20   0 2562816 553112 128492 S   0.7  3.4   2:41.20 firefox                               
    16 root      20   0       0      0      0 S   0.3  0.0   0:01.05 ksoftirqd/1                           
   708 root     -51   0       0      0      0 S   0.3  0.0   0:01.20 irq/95-ELAN1000                       
  1302 root     -51   0       0      0      0 S   0.3  0.0   0:03.68 irq/142-nvidia                        
  1734 asus      20   0  483388  11060   8560 S   0.3  0.1   0:05.45 conky                                 
  2820 root      20   0       0      0      0 S   0.3  0.0   0:00.14 kworker/5:1                           
  3420 asus      20   0   53384   3932   3200 R   0.3  0.0   0:00.76 top                                   

I don't know why this issue has been happend but usually it's occured when run some commands like sudo apt update .

(I'm using tor and obfs4proxy, It's may be helpful for answer)

I was install ubuntu 16.04 with 'install ubuntu alongside windows' option that do anythings like Partitioning by default.

But when I check the swap partition size by swapon -s command, this output has been shown :

Filename                Type        Size    Used    Priority
/dev/sda8                               partition   58039292    0   -1

And here is my free -h command output :

              total        used        free      shared  buff/cache   available
Mem:            15G        982M         13G        130M        1.2G         14G
Swap:           60G          0B         60G

As you seen I have 16G ram and 60G swap partition. (and I have windows alongside ubuntu)

Is this normal to set 60G for swap partition ? (beacause it is much more than 2xram)

When sudo apt-get install -y blender redirects to /dev/null , the installing process completed without any warnings or errors.

But when sudo apt install -y blender redirects to /dev/null , this warning is shown :

WARNING: apt does not have a stable CLI interface. Use with caution in scripts.

So what's difference between apt-get and apt commands that cause this warning ?

I know that it's better to use apt instead of apt-get, but how to redirect the apt output without this warning ?

Is there another way to make apt less noisy ? (beacause -q and -qq options are not silently as they be should)

As you know when we are use apt-get update , it updates packages list .

So when we want to install an application or upgrade the older ones, it's better to run apt-get update command to install the Latest application or upgrade to the Latest one .

And here is the question :

What can I do to run apt-get update command automatically, when I run apt-get install Application or apt-get upgrade commands ?

Update : I'm using Ubuntu 16.04 distribution .

When I was restarting Xubuntu, the firefox was started at startup.

But when I was going to Session and Startup, firefox is not there!

And here is the ls /etc/xdg/autostart/ output :

at-spi-dbus-bus.desktop            onboard-autostart.desktop
baloo_file.desktop                 pam_kwallet_init.desktop
blueman.desktop                    plasmashell.desktop
gnome-keyring-pkcs11.desktop       polkit-gnome-authentication-agent-1.desktop
gnome-keyring-secrets.desktop      polkit-kde-authentication-agent-1.desktop
gnome-keyring-ssh.desktop          powerdevil.desktop
gnome-software-service.desktop     print-applet.desktop
gsettings-data-convert.desktop     pulseaudio.desktop
indicator-application.desktop      update-notifier.desktop
indicator-messages.desktop         user-dirs-update-gtk.desktop
indicator-sound.desktop            xembedsniproxy.desktop
kdeconnectd.desktop                xfce4-clipman-plugin-autostart.desktop
klipper.desktop                    xfce4-notes-autostart.desktop
krunner.desktop                    xfce4-power-manager.desktop
light-locker.desktop               xfce4-volumed.desktop
nautilus-autostart.desktop         xfsettingsd.desktop
nm-applet.desktop                  xscreensaver.desktop
nvidia-settings-autostart.desktop

Update: I was trying this command later but firefox not apeared :

cd /etc/xdg/autostart/ && sudo sed --in-place 's/NoDisplay=true/NoDisplay=false/g' *.desktop

And here is the question, how can I disable firefox from startup?

My /etc/apt/sources.list contains this line :

deb http://downloads.sourceforge.net/project/xenlism-wildfire/repo deb/ 

I want to remove that line via sed in command line, so I tried this code but returns error !

$ sudo sed 's:deb http://downloads.sourceforge.net/project/xenlism-wildfire/repo deb/::g' /etc/apt/sources.list
sed: -e expression #1, char 75: unknown option to `s'

I guess the symbol : after http caused this error, but how can I fix it?

I have two problems :

1. Fn+F5 doesn't work on my keyboard to control brightness, so I change /etc/default/grub and add pcie_aspm=force acpi_osi= at the end of quiet splash and my problem was solved.

2. After rebooting my laptop, it was freezing during reboot so I added reboot=acpi at the end of that phrase but it didn't work for me (when I was adding that at the end of quiet splash it works well but after I was adding pcie_aspm=force acpi_osi= to grub reboot=acpi does not work).