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Connecting WWAN Modem in Linux

As of this writing Linux support about this type of modem isn’t really good. GUI Network Manager doesn’t know such device. You need to configure it manually (in console). The solution that works for me.
First

$ echo -e “AT^NDISDUP=1,1,\”your_APN_name\”\r” > /dev/ttyUSB0

This command will connect the stick to LTE network.

Assuming:
– You have installed usb_modeswitch package
– the modem created /dev/ttyUSB0
– your modem has no qmi and no mbim. It just works with AT command.

Then

$ su -c dhclient wwan0

This command will acquire IP address for the wwan0 interface.

Various notes:
– When this device connected to internet, your network manager software will recognized the connection as ‘Wired Connection’.
– if your WWAN modem is QMI device, you probably need to use qmcli to configure your device.
– if your WWAN modem is MBIM device, you probably need to use mmcli to configure your device.

Source:
How to enable broadband connection with Huawei E3372h on Ubuntu Server
How To Use LTE modem in QMI mode for WAN connection
What is libqmi?
What is libmbim?

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Tweaking Swappiness Setting in Linux

The default value setting for swappiness is 60. Meaning that the swap file will be used fairly often if the memory usage is around half of your RAM. Some suggested that reducing the default value of swappiness will probably improve overall performance for a typical Linux desktop installation. A value of swappiness=10 is recommended. The swap file will then only be used when my RAM usage is around 90 percent. Feel free to experiment.
To change the system swappiness value, open /etc/sysctl.conf as root. Then, change or add this line to the file:

vm.swappiness = 10

Reboot for the change to take effect.

Source:
How do I configure swappiness? | Ask Ubuntu
Why most people recommend to reduce swappiness to 10-20? | Ask Ubuntu
Why is swappiness set to 60 by default? | Unix & Linux Stack Exchange

Using dd to Create a Bootable USB Linux System from .iso File

This short tutorial assumes you build the bootable USB from a Linux system (not from Windows or Mac).
– First make an hybrid ISO from your distro .iso file using isohybrid tool. This step isn’t required if your .iso  are already a hybrid.

$ isohybrid your_iso_file.iso

You might see an error when issuing the command

Warning: more than 1024 cylinders (1620).Not all BIOSes  will be able to boot this device

Don’t worry about it.The warning refers to very old BIOSes.

– Then use dd to write that hybrid ISO to your USB drive.

$ dd if=your_iso_file.iso of=/dev/sdX

Replace the your_iso_file with the name of your .iso file.
Replace the /dev/sdX with the path to the USB drive. Note: the path to the USB drive (/dev/sdX) you want to write to must not contain a partition letter.  So it should look like /dev/sdb not /dev/sdb1.
Also, the dd command does not provide indicator for progression while it is running in the console. Just wait for a little while.

Source:
Create USB Boot Stick | PCLinuxOS forum
HOWTO: Create a bootable Linux Media using the dd Command | Toolbox.com

How to “Pin” a Package in Synaptic

To “pin” a software package in Synaptic from being updated (for whatever reason), you just simply need to “lock the version.”
Find and select the package you wish to hold back.Then go to Package > Lock Version in the menu bar.

Source:
How to hold a package back from being upgraded? | AskUbuntu

Location for Kate’s Syntax Highlighting Files

It’s in ~/.kde4/share/apps/katepart/syntax. The exact location may be slightly different in various Linux distros.

Source:
Writing a Syntax Highlighting File | Kate-Editor.org

Youtube’s HTML5 Player and 1080p in Firefox(Linux)

1.Activating HTML5 player
As of this writing it is not activated by default in Firefox. It has something to do about Media Source Extensions, not activated by default in Firefox.
Go to https://www.youtube.com/html5 and “Select the HTML5 player” to activate the HTML5 player.

2.Get the 1080p stuff
To get Full HD resolution you need to enable both Media Source Extensions in general and MSE + WebM in Firefox.
-Type about:config in the address and Click “I’ll be careful, I promise”
– Type mediasource in searchbox. Double-click both media.mediasource.enabled and media.mediasource.webm.enabled in order to change their value to “true”. Read More…

Solution for Virtualenv Error : ‘Unable to Execute bla bla Permission Denied ‘

So I got this error when creating a virtualenv on a different partition other than my /home folder.

ERROR: The executable myenv/bin/python3.4 could not be run: [Errno 13] Permission denied

Turns out this problem related to the default permission when creating a partition which didn’t enable exec option on my partition. So, I enable the exec option by editing /etc/fstab .
Before

# Entry for /dev/sda7 :
/dev/sda7 /media/sda7 ext4 user 1 2

After

# Entry for /dev/sda7 :
/dev/sda7 /media/sda7 ext4 user,exec 1 2

Note the addition of ‘exec’.

Reference:
strange permissions problems for virtualenv python executable (lubuntu-12.10) | StackOverFlow