the return of the system () call to/bin/sh failure, so it is better to check the errno again to confirm that the execution was successful.
Additional Instructions
Do not use System () when writing programs with Suid/sgid permissions, and System () inherits environment variables, which can cause system
Usually go out to carry a notebook computer, then save the use of notebook batteries is very necessary, we can use notebook computer users will often switch computer management functions to better energy saving, general switching notebook power management functions will also be more trouble, need to pass Ghost Win7 Control Panel and then select Power Options management settings, in fact, we can switch noteb
#确认jdk版本/usr/libexec/java_home#会得到下面信息 (different versions are displayed differently)/library/java/javavirtualmachines/jdk1.7.0_60.jdk/contents/home#上面是1. Version 7 JDK, you can use the-V ID to get other installed versions of the JDK, such as: The 1.6 version of the JDK that comes with the system/usr/libexec/java_home-v ' 1.6* '#会得到下面信息 (Mac OS X 10.9.4 comes with 1.6JDK)/system/library/java/javavirtualmach
Switch the operating system from windows to linux or windows linux
For developers, the windows system has some natural defects, such as: far-fetched command lines, File Name Length directory depth restrictions, encoding and line breaks. After several pitfalls, switch from windows to linux mint. (PS: the programmer's g
with 8088/8086 falling from the sky, it is only a way to access memory, and for 8086/8088, it has only real mode this kind of memory addressing mode, and for 80286 including its future CPU, There are two ways to address both real and protected modes, because system compatibility is a considerationObviously with the upgrading of the CPU, 8088/8086 of the memory addressing mode has been unable to meet the needs, it can be said that in order to access m
Repeater, Hub, switch, and router are all devices generated for different layers of the OSI Layer-7 network model. One by one, they are summarized as follows:
Repeater: Repeater
Is a connection device of the network physical layer, which works on the OSI physical layer. In fact, it is a signal amplifier. It is only responsible for transmitting signals from one cable to another. It can only be connected to the same type of CIDR Block and cannot be co
I use the WIN8 system, now I want to play the desktop background automatically, how can I play the desktop background automatically in the WINDOWS8?
Operation Steps
1, landing Windows8 System Metro interface, click the lower left-hand corner of the desktop icon, the following figure:
2, into the desktop, the blank place right click-Personalized, the following figure:
3, into pers
If you Win7 a system installation, you will always see a prompt when you turn it on or off: "Windows update configuration ... Do not turn off the computer prompts ", seriously affecting the speed of our switching machine, even if the shutdown speed how can slow it!" Why does Win7 jump out of update? Win7 how to turn off update? The following small editor teaches you to solve this problem with simple settings.
Let's start with the reason! In fact, Win
The Windows directory defaults to C, and when using tools such as Python, the working directory is usually on a different disk and needs to switch directories, and the window system's directory switch is not the same as Linux. If the working directory is E:\code\python, the method is as follows:1. Open cmd Command Window2, enter E:, enter the E-drive3, enter CD Code\python4,dir command to view file details
System Switch Machine commandDescription-The server does not shut down frequently, restarts, does not fail, and the server does not shut down. So these commands don't seem to be very common.1, Shutdown/usr/sbin/shutdowne.g.Shutdown-h 0# shuts down immediately , but it is best not to use this command on the server.2, Reboot/usr/sbin/reboote.g.Reboot system restart
specific to formula.
brew outdated
List formulae that have an updated version available (brew install formulaWill install the newer version)
brew prune
Remove dead symlinks from homebrew's prefix4
brew remove [formula]
Uninstallformula
brew search
List all available Formula
brew search [formula]
SearchformulaIn all available Formulae
brew search /[formula]/
Search/formula/(As RegEx) in all available Formulae
brew u
/winFonts2. Then copy the font files to this folder:sudocp~/Desktop/font/*.ttf/usr/share/fonts/winFonts/3. Then, change the permissions:sudochmod644/usr/share/fonts/winFonts/*.ttf(Change to 755 is no problem, but at least 444, modify the JAS Black font file permissions of 644, that is, the current user read and write, the current group of users read-only, other users read only)4. Start the installation:cd/usr/share/fonts/winFonts/sudomkfontscale(创建雅黑字体的fonts.scale文件,它用来控制字体旋转缩放)sudomkfontdir(创建雅
When su is used to switch to the root, the system prompts: cannotsetgroups: The operation is not allowed-Linux Enterprise Application-Linux server application information. The following is the details. Switch to the/bin directory and use ls-l to check whether the su File Permission is rwxr-xr-x or-rwxrwxrwx. If yes, run the following command:
Chmod ug + s su
controllable classloader, And the definition class loader of the module is released for reference; release instance references of all classes of this module; release Class Object references of this module.
Also, the module defines the class loaders, class instances, and class objects. As long as they are not referenced in other modules, they are not in the stack memory, you can uninstall the module. In particular, the module itself references these things, especially the static variables of the
1, in the Windows 10 desktop selected "This Computer" right click, pop-up menu select "Properties" effect is as follows;
2, into the first system interface we switch to "advanced system settings" as shown in the following image click it;
3, then in the entry of the "Advanced" interface we click-Start and failback below the "setting" effect
intelliitrace" --> OK
Click Advanced to find the location of the record, copy the file path, and locate the corresponding folder to find the root cause of the problem.
It turns out that such a folder is used to store files that can only be tracked. Right-click the folder and check the file size. The folder size is 7.77 GB ,:
What is the file stored in this folder ?. The itrance file, that is, the smart tracking file for debugging.
What is the file? Opening it with notepad is a bunch o
In the Win7 system, the toolbar provides us with many convenient functions, such as window preview and so on. However, some users who use multiple pages to play web games feel that the toolbar is not fast enough to switch time, want to speed up the speed of the toolbar, what method? The following small series to teach you how to use the registry to promote the Win7 Syst
For help .. Fedaro9.0 is unable to access the Internet after a dual-system switch-general Linux technology-Linux technology and application information. For details, refer to the following section. Hello, everyone. I use dual-systems of fedaro9.0 and xp. At home, I use a Broadband Router to access the Internet through China Telecom adsl Broadband ..
Now I have a question: why can I use dhcp to obtain the
How to switch the Ubuntu 12.04 Chinese system back to English sometimes my colleagues may accidentally install the Chinese version. It is not a poor Chinese character, but an error message or a Chinese character that cannot be found on the Internet. The following method can be used to restore the English system.1. in the/etc/default/locale file, replace all zh_CN
Win7 System Press shortcut key Ctrl+shift switch Input method does not respond to do
Method One:
1, on the taskbar right click, click "Task Manager";
2, in the "Process" tab check whether there is "ctfmon.exe";
3, if not, click on Task Manager "file" Click to run a new task, input ctfmon.exe and enter;
4, if the prompt error, is the machine's Ctfmon.exe file damaged or lost, to the same
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