Manual conversion

1. Open the file in the GIMP (make sure you have ghostscript installed! — Windows Ghostscript installation instructions)
   • Enter 500 in the “resolution” input box
   • You may need to uncheck “try bounding box”, since the bounding box sometimes cuts off part of the image.
     • Enter large values for Height and Width if not using the bounding box
   • Select color
   • Select strong anti-aliasing for both graphics and text
2. Crop off extra whitespace (shift+C if you can’t find it in the toolbox)
3. Image → Transform → Rotate 90 degrees clockwise
4. Filters → Blur → Gaussian blur (No need to blur if you use strong anti-aliasing during conversion. No significant difference between end results.)
   • 2.0 px
5. Image → Scale Image…
   • 25%
   • Cubic interpolation
6. You can view at normal size if you want by pressing 1, Ctrl+E
7. Save as File_name.png

• The GIMP documentation

Command-line method

Another route to convert a PS or EPS file (postscript) in png is to use ImageMagick, available on many operating systems. A single command is needed:

convert -density 300 file.ps file.png

The density parameter is the output resolution, expressed in dots per inch. With the standard 5×3.5in size of a gnuplot graph, this results in a 1500×1050 pixels PNG image. ImageMagick automatically applies antialiasing, so no post-processing is needed, making this technique especially suited to batch processing. The following Makefile automatically compiles all gnuplot files in a directory to EPS figures, converts them to PNG and then clears the intermediate EPS files. It assumes that all gnuplot files have a “.plt” extension and that they produce an EPS file with the same name, and the “.eps” extension:

GNUPLOT_FILES = $(wildcard *.plt)
# create the target file list by substituting the extensions of the plt files
FICHIERS_PNG = $(patsubst %.plt,%.png,  $(GNUPLOT_FILES))

all: $(FICHIERS_PNG)

%.eps: %.plt
	@ echo "compillation of "$<
	@gnuplot $<

%.png: %.eps
	@echo "conversion in png format"
	@convert -density 300 $< $*.png
	@echo "end"

What is EPS file format?

Encapsulated PostScript (EPS) is a standard file format for importing and exporting PostScript files. It is usually a single page PostScript program that describes an illustration or an entire page. The purpose of an EPS file is to be included in other pages. Sometimes EPS files are called EPSF files. EPSF simply stands for Encapsulated PostScript Format.

An EPS file can contain any combination of text, graphics and images. Since it is actually a PostScript file, it is one of the most versatile file formats that are available. EPS-files usually contain a small preview image that is used to visualize the content of the file.

See also:

   http://mintaka.sdsu.edu/GF/bibliog/latex/PSandPNG.html

   http://electron.mit.edu/~gsteele/pdf/

Here is simple synchronization script using lftp.



lftp ftpsite

lftp -u username,password ftpsite.

mirror path/to/source_directory path/to/target_directory

lftp -u username,password -e "mirror --delete --only-newer --verbose path/to/source_directory path/to/target_directory" ftpsite

lftp -f /home/user/ftpscript.txt

lftp at 00:00 -u username,password -e "mirror --delete --only-newer --verbose path/to/source_directory path/to/target_directory" ftpsite &

lftp -u username,password -e "mirror --reverse --delete --only-newer --verbose path/to/source_directory path/to/target_directory" ftpsite

Read from remote host ocaoimh.ie: Connection reset by peer
Connection to ocaoimh.ie closed.

There’s a quick fix for that. Actually, there are 2 ways to fix it. You only need to do one of them so choose whichever one is easiest for you. You’ll need root access, so for most people it’s probably safer to do the client fix rather than the server fix.

• On the server, login as root and edit /etc/ssh/sshd_config and add the line:
  

  ClientAliveInterval 60

  According to man sshd_config, this line,

  Sets a timeout interval in seconds after which if no data has been received from the client, sshd(8) will send a message through the encrypted channel to request a response from the client. The default is 0, indicating that these messages will not be sent to the client. This option applies to protocol version 2 only.

  Don’t forget to restart sshd on the server after you save the file.

• The other way, and easier and safer way is for your desktop machine to send those keep alive messages. As root on your desktop (or client) machine, edit /etc/ssh/ssh_config and add the line:
  

  ServerAliveInterval 60

  That will send send a message to the server every 60 seconds, keeping the connection open. I prefer this way because I login to several machines every day, and I don’t have root access to all of them.

The scp command allows you to copy files over ssh connections. This is pretty useful if you want to transport files between computers, for example to backup something. The scp command uses the ssh command and they are very much alike. However, there are some important differences.

The scp command can be used in three* ways: to copy from a (remote) server to your computer, to copy from your computer to a (remote) server, and to copy from a (remote) server to another (remote) server. In the third case, the data is transferred directly between the servers; your own computer will only tell the servers what to do. These options are very useful for a lot of things that require files to be transferred, so let’s have a look at the syntax of this command:

[rechosen@localhost ~]$ scp examplefile yourusername@yourserver:/home/yourusername/

Looks quite familiar, right? But there are differences. The command above will transfer the file “examplefile” to the directory “/home/yourusername/” at the server “yourserver”, trying to get ssh acces with the username “yourusername”. That’s quite a lot information, but scp really needs it all. Well, almost all of it. You could leave out the “yourusername@” in front of “yourserver”, but only if you want to login on the server with your current username on your own computer. Let’s have a closer look at the end of the command. There’s a colon over there, with a directory after it. Just like Linux’s normal cp command, scp will need to know both the source file(s) and the target directory (or file). For remote hosts, the file(s)/directory are given to the scp command is this way.

You can also copy a file (or multiple files) from the (remote) server to your own computer. Let’s have a look at an example of that:

[rechosen@localhost ~]$ scp yourusername@yourserver:/home/yourusername/examplefile .

Note: The dot at the end means the current local directory. This is a handy trick that can be used about everywhere in Linux. Besides a single dot, you can also type a double dot ( .. ), which is the parent directory of the current directory.

This will copy the file “/home/yourusername/examplefile” to the current directory on your own computer, provided that the username and password are correct and that the file actually exists.

You probably already guessed that the following command copies a file from a (remote) server to another (remote) server:

[rechosen@localhost ~]$ scp yourusername@yourserver:/home/yourusername/examplefile yourusername2@yourserver2:/home/yourusername2/

Please note that, to make the above command work, the servers must be able to reach each other, as the data will be transferred directly between them. If the servers somehow can’t reach each other (for example, if port 22 is not open on one of the sides) you won’t be able to copy anything. In that case, copy the files to your own computer first, then to the other host. Or make the servers able to reach each other (for example by opening the port).

Well, those are the main uses of scp. We’ll now go a bit more in-depth about the differences between ssh and scp.

*: Actually you can also use it just like the normal cp command, withhout any ssh connections in it, but that’s quite useless. It requires you to type an extra ‘s’ =).

Specifying a port with scp

The scp command acts a little different when it comes to ports. You’d expect that specifying a port should be done this way:

[rechosen@localhost ~]$ scp -p yourport yourusername@yourserver:/home/yourusername/examplefile .

However, that will not work. You will get an error message like this one:

cp: cannot stat `yourport’: No such file or directory

This is caused by the different architecture of scp. It aims to resemble cp, and cp also features the -p option. However, in cp terms it means ‘preserve’, and it causes the cp command to preserve things like ownership, permissions and creation dates. The scp command can also preserve things like that, and the -p option enables this feature. The port specification should be done with the -P option. Therefore, the following command will work:

[rechosen@localhost ~]$ scp -P yourport yourusername@yourserver:/home/yourusername/examplefile .

Also note that the -P option must be in front of the (remote) server. The ssh command will still work if you put -p yourport behind the host syntax, but scp won’t. Why? Because scp also supports copying between two servers and therefore needs to know which server the -P option applies to.

Another difference between scp and ssh

Unlike ssh, scp cannot be used to run a command on a (remote) server, as it already uses that feature of ssh to start the scp server on the host. The scp command does have an option that accepts a program (the -S option), but this program will then be used instead of ssh to establish the encrypted connection, and it will not be executed on the remote host.

Tips & Tricks with ssh and scp

Quite a handy thing about scp is that it supports asterisks. You can copy all files in a remote directory in a way like this:

[rechosen@localhost ~]$ scp yourusername@yourserver:/home/yourusername/* .

And you can also just copy a whole directory by specifying the -r (recursive) option:

[rechosen@localhost ~]$ scp -r yourusername@yourserver:/home/yourusername/ .

Both of these also work when copying to a (remote) server or copying between a (remote) server and another (remote) server.

The ssh command can come in handy if you don’t know the exact location of the file you want to copy with scp. First, ssh to the (remote) server:

[rechosen@localhost ~]$ ssh yourusername@yourserver

Then browse to the right directory with cd. This is essential Linux terminal knowledge, so I won’t explain it here. When you’re in the right directory, you can get the full path with this command:

[rechosen@localhost ~]$ pwd

Note: pwd is an abbreviation of Print Working Directory, which is a useful way to remember the command.

You can then copy this output, leave the ssh shell by pressing Ctrl + D, and then paste the full directory path in your scp command. This saves a lot of remembering and typing!

You can also limit the bandwidth scp may use when copying. This is very useful if you’re wanting to copy a huge amount of data without suffering from slow internet for a long time. Limiting bandwidth is done this way:

scp -l bandwidthlimit yourusername@yourserver:/home/yourusername/* .

The bandwidth is specified in Kbit/sec. What does this mean? Eight bits is one byte. If you want to copy no faster than 10 Kbyte/sec, set the limit to 80. If you want to copy no faster than 80 Kbyte/sec, set the limit to 640. Get it? You should set the limit to eight times the maximum Kbyte/sec you want it to be. I’d recommend to set the -l option with all scp’ing you do on a connection that other people need to use, too. A big amount of copying can virtually block a whole 10 Mbit network if you’re using hubs.

1. 显示行号
:set number
2. 取消行号显示
:set nonumber
3. 跳到一特定行 （必须得在命令模式，好像必须每次都得先按Esc键）

回到第一行： G

跳到特定行如99行：  99G

vsftpd problem – 500 OOPS: could not bind listening IPv4 socket

sudo /etc/init.d/vsftpd sta

sudo /etc/init.d/vsftpd stop

1、安装 X 窗口系统：sudo apt-get install x-window-system-core

2、安装登录管理器：sudo apt-get install xdm/gdm/kdm[注]。最常见的图形化登录管理器包括 XDM、GDM、KDM，用户可根据自己的需要选择其中之一

3、 安装桌面环境或窗口管理器：sudo apt-get install ubuntu-desktop/kubuntu-desktop/xubuntu-desktop。这将分别安装 GNOME、KDE、XFCE 桌面环境。对于 GNOME、KDE、XFCE 这些桌面环境来说，为了获得更强的定制效果，也可仅安装最基本的组件，如：sudo apt-get install gnome-core/kde-core/xfce4。

如果不需要桌面环境，也可选择安装窗口管理器代替。那样的话，可以执行指令 sudo apt-get install fluxbox/icewm/enlightenment/fvwm