20141915-2 选题

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Potenza Icon Themes 2.0 Available For Download
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![](http://itsfoss.itsfoss.netdna-cdn.com/wp-content/uploads/2014/09/Potenza_Icons.jpeg)
[Potenza][1] Icon Theme version 2.0 has been released. Potenza icons are inspired by [Faenza][2], a beautiful icon theme that was included in our list of [best icons for Ubuntu 13.10][3].
Potenzas developer Alessandro Bompadre says that he has tried to create a complete iconset for Linux, that should fit every desktop environment such as Unity, GNOME, Cinnamon, KDE etc.
### Download Potenza icon them ###
Potenza icons are available via Noobslabs PPA that you can use in Ubuntu, Linux Mint, Elementary OS, Linux Lite etc. Just a word of warning, since there are a huge number of icons for all major kind of desktop environments, the total download size will be around 400 MB.
Open a terminal and use the following commands:
sudo add-apt-repository ppa:noobslab/potenza
sudo apt-get update
sudo apt-get install potenza-2
If you dont want to use the PPA, you can install the icon theme from the link below:
- [Download Potenza icon theme][4]
Extract the zipped file in ~/.icons directory. In Ubuntu Unity, you can [use Unity Tweak Tool to change the current icon theme][5] to Potenza.
I hope you like Potenza, you should also check [Dalisha icon themes][6] or check our list of [best icon themes for Ubuntu 14.04][7].
--------------------------------------------------------------------------------
via: http://itsfoss.com/potenza-icon-themes-20-download/
作者:[Abhishek][a]
译者:[译者ID](https://github.com/译者ID)
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[a]:http://itsfoss.com/author/Abhishek/
[1]:https://github.com/AlessandroBompadre/Potenza/
[2]:http://tiheum.deviantart.com/art/Faenza-Icons-173323228
[3]:http://itsfoss.com/best-icon-themes-ubuntu-1310/
[4]:http://gnome-look.org/content/show.php/Potenza+2.0?content=166853
[5]:http://itsfoss.com/best-icon-themes-ubuntu-1404/
[6]:http://itsfoss.com/dalisha-icon-ubuntu-linux/
[7]:http://itsfoss.com/best-icon-themes-ubuntu-1404/

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How To Uninstall Ubuntu Linux From Windows 8 Dual Boot
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![](http://itsfoss.itsfoss.netdna-cdn.com/wp-content/uploads/2014/09/Guide_Uninstall_Ubuntu_Windows_dual_Boot.jpeg)
I have covered [how to install Ubuntu in dual boot with Windows 8][1]注此篇文章原文做过原文文件名为Guide To Install Ubuntu 14.04 In Dual Boot Mode With Windows 8 Or 8.1 UEFI.md如果翻译发布了可以修改此链接。 several times in the past. But what about **uninstalling Ubuntu from Windows dual boot**? Tutorial which we are going to follow here applies on any Linux OS be it Ubuntu, Linux Mint, Elementary OS or any other Linux distribution.
If you think [installing Ubuntu with Windows 8 in dual boot][2] was a tough task and it will be very easy to remove Ubuntu from Windows dual boot, you are not completely wrong. Uninstalling Linux from Windows dual boot is a piece of cake if you have a Windows installation disk.
This tutorial teaches you how to remove Linux completely from Windows 8 or Windows 8.1 dual boot with a **Windows 8/8.1 installation disk**.
### Uninstall Ubuntu safely from Windows 8 dual boot mode ###
It doesnt matter if you have Windows 8 installation disk and Windows 8.1 installed on your system. It will work all the same. I cannot say the same of Windows 7 though. If you have your Windows disk with you, lets start the process to remove Ubuntu Linux from Windows dual boot.
Deleting Linux from dual boot is done in two parts. First is to delete the partition(s) on which Linux was installed. Second part is to fix Windows boot loader as just deleting the Linux partition will result in [Grub rescue error][3].
#### Part 1: Deleting Linux partition in Windows ####
**Step 1:**
Log in to Windows. Press **Windows+R** and run diskmgmt.msc command in it. It will open the Windows disk management tool.
![](http://itsfoss.itsfoss.netdna-cdn.com/wp-content/uploads/2014/09/Disk_Mgmt.jpg)
**Step 2:**
Since you had installed Linux, it will be easy for you to recognize the Linux partition by its size. Another hint to recognize the Linux partition is to look at the partitions which doesnt have a file system and drive number. Windows partition are labeled with a drive number such as C, D, E etc and are usually in NTFS or FAT file system.
As you can see, I have three Linux partitions here as I had created root, swap and home separately while installing Ubuntu.
![](http://itsfoss.itsfoss.netdna-cdn.com/wp-content/uploads/2014/09/Uninstall_Linux_From_WIndows_Dual_Boot.jpg)
**Step 3:**
Select the Linux partition(s), right click on it and opt for **Delete Volume** option.
![](http://itsfoss.itsfoss.netdna-cdn.com/wp-content/uploads/2014/09/Uninstall_Linux_From_WIndows_Dual_Boot_1.jpg)
It will throw you a warning, just select Yes here.
![](http://itsfoss.itsfoss.netdna-cdn.com/wp-content/uploads/2014/09/Uninstall_Linux_From_WIndows_Dual_Boot_2.jpg)
**Step 4:**
The deleted partition(s) will be available as a chunk of free space. You can either extend the existing volume or create a new Windows partition out of it. I would suggest to create a new drive (or volume or partition, whatever you call it) as a new drive would be easier in case you decide to dual boot Linux with Windows again.
![](http://itsfoss.itsfoss.netdna-cdn.com/wp-content/uploads/2014/09/Uninstall_Linux_From_WIndows_Dual_Boot_3.jpg)
#### Part 2: Fixing Windows boot loader ####
Once you have deleted the Linux partition, its time to fix the Windows boot loader. Pictures here are might not be that clear as it is easier to [take screenshot of login screen in Ubuntu][4] than in Windows. I took them with phone camera.
**Step 1:**
**Put the Windows 8 installation disk and restart** your computer. Press F10 or F12 at the boot time to go into BIOS/UEFI and choose to **boot from removable disk**.
![](http://itsfoss.itsfoss.netdna-cdn.com/wp-content/uploads/2014/09/Uninstall_Linux_Windows_Dualboot_1.jpg)
**Step 2:**
Choose to repair your computer:
![](http://itsfoss.itsfoss.netdna-cdn.com/wp-content/uploads/2014/09/Uninstall_Linux_Windows_Dualboot_3.jpg)
**Step 3:**
Go for Troubleshoot option here:
![](http://itsfoss.itsfoss.netdna-cdn.com/wp-content/uploads/2014/09/Uninstall_Linux_Windows_Dualboot_2.jpg)
**Step 4:**
In troubleshoot page, choose for Advanced options:
![](http://itsfoss.itsfoss.netdna-cdn.com/wp-content/uploads/2014/09/Uninstall_Linux_Windows_Dualboot_4.jpg)
**Step 5:**
Look for command prompt option in here:
![](http://itsfoss.itsfoss.netdna-cdn.com/wp-content/uploads/2014/09/Uninstall_Linux_Windows_Dualboot_6.jpg)
**Step 6:**
In the command line, type the following command to fix the Windows boot loader:
bootrec.exe /fixmbr
Normally, it works instantly. You dont even have to wait for it.
![](http://itsfoss.itsfoss.netdna-cdn.com/wp-content/uploads/2014/09/Uninstall_Linux_Windows_Dualboot_5.jpg)
**Step 7:**
Once its done, restart your computer and this time boot normally from hard disk. You should be able to boot in to Windows. In case you still see Grub rescue error, try the steps below.
**Step 8: If trick in step 6 did not work**
If the command in step 6 did not work, try the automatic repair option in advanced troubleshoot option.
![](http://itsfoss.itsfoss.netdna-cdn.com/wp-content/uploads/2014/09/Uninstall_Linux_Windows_Dualboot_8.jpg)
It will take some time to find the issue and then repair it.
![](http://itsfoss.itsfoss.netdna-cdn.com/wp-content/uploads/2014/09/Uninstall_Linux_Windows_Dualboot_7.jpg)
Now if you reboot, you should go in Windows normally and you should not see any Grub rescue error thingy.
I hope this guide helped you to **completely remove Ubuntu from Windows 8 dual boot**. Feel free to ask any questions or put up a suggestion.
--------------------------------------------------------------------------------
via: http://itsfoss.com/uninstall-ubuntu-linux-windows-dual-boot/
作者:[Abhishek][a]
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校对:[校对者ID](https://github.com/校对者ID)
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[a]:http://itsfoss.com/author/Abhishek/
[1]:http://itsfoss.com/install-ubuntu-1404-dual-boot-mode-windows-8-81-uefi/
[2]:http://itsfoss.com/install-ubuntu-dual-boot-mode-windows/
[3]:http://itsfoss.com/solve-error-partition-grub-rescue-ubuntu-linux/
[4]:http://itsfoss.com/screenshot-login-screen-ubuntu-linux/

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Linux FAQs with Answers--How to capture TCP SYN, ACK and FIN packets with tcpdump
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> **Question**: I want to monitor TCP connection dynamics (e.g., three-way handshake for connection establishment, and four-way handshake for connection tear-down). For that, I need to capture only TCP control packets such as those with SYN, ACK or FIN flag set. How can I use tcpdump to capture TCP SYN, ACK, and/or FYN packets only?
As a de-facto packet capture tool, tcpdump provides powerful and flexible packet filtering capabilities. The libpcap packet capture engine which tcpdump is based upon supports standard packet filtering rules such as 5-tuple packet header based filtering (i.e., based on source/destination IP addresses/ports and IP protocol type).
The packet filtering rules of tcpdump/libpcap also supports more general packet expressions, where arbitrary byte ranges in a packet are checked with relation or binary operators. For byte range representation, you can use the following format:
proto [ expr : size ]
"proto" can be one of well-known protocols (e.g., ip, arp, tcp, udp, icmp, ipv6). "expr" represents byte offset relative to the beginning of a specified protocol header. There exist well-known byte offsets such as tcpflags, or value constants such as tcp-syn, tcp-ack or tcp-fin. "size" is optional, indicating the number of bytes to check starting from the byte offset.
Using this format, you can filter TCP SYN, ACK or FIN packets as follows.
To capture only TCP SYN packets:
# tcpdump -i <interface> "tcp[tcpflags] & (tcp-syn) != 0"
To capture only TCP ACK packets:
# tcpdump -i <interface> "tcp[tcpflags] & (tcp-ack) != 0"
To capture only TCP FIN packets:
# tcpdump -i <interface> "tcp[tcpflags] & (tcp-fin) != 0"
To capture only TCP SYN or ACK packets:
# tcpdump -r <interface> "tcp[tcpflags] & (tcp-syn|tcp-ack) != 0"
![](https://farm4.staticflickr.com/3923/15050566798_db14aea9a9_z.jpg)
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Linux FAQs with Answers--How to change hostname on CentOS or RHEL 7
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> Question: What is a proper way to change hostname on CentOS / RHEL 7 (permanently or temporarily)?
In CentOS or RHEL, there are three kinds of hostnames defined: (1) static, (2) transient, and (3) pretty. The "static" hostname is also known as kernel hostname, which is initialized from /etc/hostname automatically at boot time. The "transient" hostname is a temporary hostname assigned at run time, for example, by a DHCP or mDNS server. Both static and transient hostnames follow the same character restriction rules as Internet domain names. On the other hand, the "pretty" hostname is allowed to have a free-form (including special/whitespace characters) hostname, presented to end users (e.g., Dan's Computer).
In CentOS/RHEL 7, there is a command line utility called hostnamectl, which allows you to view or modify hostname related configurations.
To view hostname related settings:
$ hostnamectl status
![](https://farm4.staticflickr.com/3844/15113861225_e0e19783a7.jpg)
To view static, transient or pretty hostname only, use "--static", "--transient" or "--pretty" option, respectively.
$ hostnamectl status [--static|--transient|--pretty]
To change all three hostnames: static, transient, and pretty, simultaneously:
$ sudo hostnamectl set-hostname <host-name>
![](https://farm4.staticflickr.com/3855/15113489172_4e25ac87fa_z.jpg)
As shown above, in case of static/transient hostnames, any special or whitespace character will be removed, and any uppercase letter will automatically be converted to lowercase in the supplied <host-name> argument. Once the static hostname is changed, /etc/hostname will automatically be updated accordingly. However, /etc/hosts will not be updated to reflect the change, so you need to update /etc/hosts manually.
If you want to change a particular hostname only (static, transient or pretty), you can use "--static", "--transient" or "--pretty" option.
For example, to change hostname permanently, you can change the static hostname:
$ sudo hostnamectl --static set-hostname <host-name>
Note that you do not have to reboot the machine to activate permanent hostname change. The above command will change kernel hostname immediately. Log out, and log back in to see the new static hostname in the command-line prompt.
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Linux FAQs with Answers--How to create a new Amazon AWS access key
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> **Question**: I was asked to provide an **AWS access key ID** and **secret access key** when configuring an application which requires access to my Amazon AWS account. How can I create a new AWS access key?
Amazon AWS security credentials are used to authenticate you and authorize any third-party application to access your AWS account. There are different types of AWS security credentials available, e.g., password, access key, multi-factor authentication, X.509 certificates, etc.
If you want to create a new access key (access key ID and secret access key), here is how to do it.
First, log in to [AWS console][1].
Choose "Security Credentials" menu from the top bar.
![](https://farm4.staticflickr.com/3855/14987093969_b106406596_o.png)
In the next page, choose "Access Keys (Access Key ID and Secret Access Key) option.
![](https://farm6.staticflickr.com/5584/15173842295_6110021f8f_z.jpg)
In the next page, you will see a list of existing access key IDs (if any). Note that you cannot retrieve "secret access keys" of existing access key IDs. For security reason, a secret access key is visible only at the time you create a new access key.
![](https://farm4.staticflickr.com/3897/15150859306_cd25d519be_o.png)
Click on "Create New Access Key", and it will create a new pair of access key ID and secret access key instantly.
![](https://farm4.staticflickr.com/3919/14987346068_232e8c73cd_z.jpg)
Either download a key file which contains a new access key, or copy and paste a new access key information. Again remember. Once you close this window, the secret access key will not be available again unless you download a key file.
### Multi-User AWS Account ###
If you are a corporate which has a corporate AWS account shared by multiple employees, you may want to use Identity and Access Management (IAM) to create and manage their access keys.
IAM is a web service which allows a corporate to manage multiple users and their associated security credentials under a single AWS account. Using IAM, multiple users can sign in as different identities under a single AWS account, and manage their own security credentials without tampering with each other's keys.
To manage IAM users, click on "Users" menu on the "Security Credentials" page.
![](https://farm6.staticflickr.com/5589/14987486468_a9120b1f8e_z.jpg)
Then you can create a new IAM user and manage their security credentials such as access keys.
--------------------------------------------------------------------------------
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[1]:http://aws.amazon.com/console/

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Linux FAQs with Answers--How to expand an XFS file system
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> **Question**: I have extra space in my disk, so I want to grow the size of an existing XFS file system created on it, in order to fully utilize the extra space. What is a proper way to expand an XFS file system?
XFS is an open-source (GPL) journaling file system originally developed by Silicon Graphics. The suport for XFS file system is available on most Linux distros nowadays. In fact, XFS has become the default file system adopted by the latest CentOS/RHEL 7. One of its many features is "online resizing", where an existing XFS file system can be expanded while it is mounted. Support for shrinking an XFS file system is not available though.
To expand an existing XFS file system, you can use a command line utility called xfs_growfs, which is available by default on most Linux distros. Since XFS supports online resizing, the target file system can be mounted or unmounted.
Here is the basic usage of **xfs_growfs**:
![](https://farm6.staticflickr.com/5551/14915082088_b4e29af3cf_z.jpg)
As the destination XFS file system to expand, you can specify either a mountpoint, a disk partition, or logical volume (in case of LVM). You specify the size of a new XFS file system as the number of data blocks. You can use xfs_info command-line tool to check data block size and the number of data blocks:
![](https://farm6.staticflickr.com/5584/14915075270_cd272d4468_z.jpg)
To extend the size of an XFS file system to 1986208:
$ sudo xfs_growfs /dev/centos/root -D 1986208
If you do not specify size with "-D" option, xfs_growfs will automatically expand an XFS file system to the largest possible size.
$ sudo xfs_growfs /dev/centos/root
![](https://farm6.staticflickr.com/5569/14914950529_ddfb71c8dd_z.jpg)
Note that when you expand an existing XFS file system, you must prepare added space for the XFS file system to grow beforehand. It may be obvious, but if there is no free space available in the underlying partition or disk volume, xfs_growfs will not do anything. Also, if you attempt to extend XFS file system size beyond the size of disk partition or volume, xfs_growfs will fail.
![](https://farm4.staticflickr.com/3870/15101281542_98a49a7c3a_z.jpg)
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Linux FAQs with Answers--How to find and remove obsolete PPA repositories on Ubuntu
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> **Question**: I was trying to re-synchronize package index files by running apt-get update. But I am getting the following "404 Not Found" errors. Looks like I cannot fetch the latest index from some third-party PPA repositories that I've added before. How can I clean up such broken and old PPA repositories?
Err http://ppa.launchpad.net trusty/main amd64 Packages
404 Not Found
Err http://ppa.launchpad.net trusty/main i386 Packages
404 Not Found
W: Failed to fetch http://ppa.launchpad.net/finalterm/daily/ubuntu/dists/trusty/main/binary-amd64/Packages 404 Not Found
W: Failed to fetch http://ppa.launchpad.net/finalterm/daily/ubuntu/dists/trusty/main/binary-i386/Packages 404 Not Found
E: Some index files failed to download. They have been ignored, or old ones used instead.
When you attempt to update APT package indexes, "404 Not Found" errors can often happen after distro upgrade. That is, after you upgraded your Ubuntu release, some third-party PPA repositories which you added on the old release are no longer supported on the upgraded release. In that case, you can **identify and purge those broken PPA repositories** as follows.
First, find out the PPAs which cause "404 Not Found" failures.
$ sudo apt-get update | grep "Failed"
![](https://farm6.staticflickr.com/5580/14972354938_0e1e1f3db6_z.jpg)
In this example, the PPA repository which is no longer supported in Ubuntu Trusty is "ppa:finalterm/daily".
Go ahead and [remove the PPA repository][1]此文原文在同一个更新中文件名“20140915 Linux FAQs with Answers--How to remove PPA repository from command line on Ubuntu.md”.
$ sudo add-apt-repository --remove ppa:finalterm/daily
You have to repeat this process for every obsolete PPA repository that you found from above.
![](https://farm4.staticflickr.com/3844/15158541642_1fc8f92c77_z.jpg)
After removing all obsolete PPA repositories, re-run "apt-get update" to check all of them have been successfully removed.
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Linux FAQs with Answers--How to remove PPA repository from command line on Ubuntu
================================================================================
> **Question**: I added a third-party PPA repository on my Ubuntu box some time ago. How can I remove the PPA repository?
A Personal Package Archives (PPA) is a Ubuntu way to allow independent developers and contributors to build and distribute any custom packages as a third-party APT repository via Launchpad. If you are a Ubuntu user, chances are that you have added some popular third-party PPA repositories to your Ubuntu system. If you want to remove any pre-configured PPA repository, here is how to do it.
Suppose you have a third-party PPA repository named "ppa:webapps/preview" added on your Ubuntu system, as follows.
$ sudo add-apt-repository ppa:webapps/preview
If you want to **delete a PPA repository alone**, run the following command.
$ sudo add-apt-repository --remove ppa:someppa/ppa
Note that the above command does not touch any packages installed or upgraded from the PPA itself.
If you want to **delete a PPA repository as well as all packages installed/upgraded from the PPA**, you can use ppa-purge command.
To install ppa-purge package:
$ sudo apt-get install ppa-purge
To remove a PPA repository and all its packages from the command line:
$ sudo ppa-purge ppa:webapps/preview
These methods can be useful when you [identify and purge broken PPA repositories][1]此文原文在同一个更新中文件名“20140915 Linux FAQs with Answers--How to find and remove obsolete PPA repositories on Ubuntu.md” after distro upgrade.
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[1]:http://ask.xmodulo.com/find-remove-obsolete-ppa-repositories-ubuntu.html