# echo 1 > /sys/devices/platform/hp-wmi/als

To disable:

# echo 0 > /sys/devices/platform/hp-wmi/als

To remap the scancode to another keycode, you can use setkeycodes. An appropriate choice for a target keycode could be KEY_PROG1 (XF86Launch1, keycode 148) which can be easily reconfigured in KDE or any other desktop environment to run any custom command.

Run the following command as root to remap Fn+F11 to KEY_PROG1:

# setkeycodes e033 148

Resources:
http://www.linlap.com/hp_elitebook_8460p

Setting a bit

foo |= 0x01;

The OR operation is used to set a particular bit that is specified in a BIT MASK. The bit mask is usually specified in hex. In this example it is 0x01 which indicates the first bit.

Clearing a bit

To clear bit 0 in foo, two different bit operations are required:

foo &= ~0x01;

This example uses the AND and the NOT operator. The NOT operator is used, because most programmers like to specify a mask, wherein the bit that should be changed, is set. You could of course just use a mask, wherein the bits that should be changed are unset, therefore eliminating the requirement for the NOT operator (note that this is highly uncommon though).

Flipping a bit

Another very useful tool is the XOR operator:

foo ^= 0x01;

This toggles the first bit, independent of its current state and leaves all other bits unchanged.

Checking if a bit is set

Because a statement anything other than zero is considered TRUE in C/C++ (and probably every other programming language, too), you can use

if(foo & 0x01) {
  (...)
}

to check, whether the first bit is set or clear.

Dynamically building a bit mask

Because it is much easier to specify the bit number that should be changed rather than the actual bit mask, programmers usually build up the bit mask dynamically. This is done by left-shifting 0x01 n-times. For example, to build a bit mask that has bit number 7 set, you left-shift 0x01 seven times:

(0x01 << 7)

To build a bit mask that has the first bit (bit number 0) set, you’d shift 0x01 zero times:

(0x01 << 0)

Become a member of dialout

Simply run

# usermod -a -G groupname username

to add the user username to the group groupname. To verify, that a certain user is a member of a specific group, you can grep the file /etc/group for a user name

# grep username /etc/group

Note that you have to re-login for this changes to take effect.

Create the device with different permissions

Alternatively, you can tell udev to create the /dev/ttyUSBX device with different read and write permissions. Add a udev rule to /etc/udev/rules.d/, e.g. /etc/udev/rules.d/85-PL2303SerialPort.rules with the following content:

ATTRS{idVendor}=="067b", ATTRS{idProduct}=="2303", MODE="0666"

You can get the vendor and product id from lsusb or by looking at /var/log/messages when you plug in the device.

After saving the new udev rule, tell udev to reload it’s ruleset

# udevadm control --reload-rules

and eventually plug in your adapter.

Usually the label is set when the partition is created. If the label is not explicitly specified, it is usually auto-generated. To change the label, there are a couple of tools available:

ext2/ext3/ext4 partitions

You can either use e2label

# e2label device [newlabel]

or tune2fs

# tune2fs -L [newlabel] device

FAT/FAT16/FAT32 partitions

Again, there are multiple tools available, from simple perl scripts to mtools, but the easiest to use is probably dosfslabel from the dosfstools package

# yum install dosfstools
[...]
# dosfslabel device [newlabel]

NTFS partitions

ntfslabel is available as part of the ntfsprogs package

# yum install ntfsprogs
[...]
# ntfslabel device [newlabel]

char <unicode>

For example, to get the degree symbol (Unicode: U+00B0) you’d type in 'char 176' (176 being 0xB0 converted do decimal).

$ yum whatprovides */libGLU.so.1

and yum would tell you, that mesa-libGLU comes with /usr/lib64/libGLU.so.1 which could fulfill your need (could because you could also be missing the i686 version of the package, depending on your binary).

The Ubuntu way of achieving the same thing:

$ apt-file search libGLU.so.1

And of course the corresponding package would be libglu1-mesa on any recent Ubuntu os.

# systemctl enable --force displaymanager.service 

Therefore, to switch from the default gdm to kdm you’d run:

# systemctl enable --force kdm.service 

To change this behaviour, add a DHCP_HOSTNAME variable to your /etc/sysconfig/network-scripts/ifcfg-eth0 file (eth0 being your NIC’s interface name):

UUID="616426f3-ac0b-4a4a-9221-62a0055bfb07"
NM_CONTROLLED="yes"
NETBOOT="yes"
BOOTPROTO="dhcp"
DHCP_HOSTNAME="MyFedoraBox"
DEVICE="eth0"
TYPE="Ethernet"
ONBOOT=yes
NAME="DHCP"
HWADDR=00:25:22:4A:3F:F2
DEFROUTE=yes
PEERDNS=yes
PEERROUTES=yes
IPV4_FAILURE_FATAL=yes
IPV6INIT=no
USERS=user

Of course, this only works if you actually get your IP address via DHCP (since the DHCP server hands off the hostname to the DNS server). If you use a static IP configuration, nsupdate can be used to dynamically update the DNS server records. Examples and instructions on how to use nsupdate can be found at http://linux.yyz.us/nsupdate/ or http://dijks.wordpress.com/2012/07/17/register-a-hostnames-static-ip-with-your-corporate-dns-server/.