diff --git a/sources/tech/20171204 How To Know What A Command Or Program Will Exactly Do Before Executing It.md b/sources/tech/20171204 How To Know What A Command Or Program Will Exactly Do Before Executing It.md deleted file mode 100644 index bc7b2c9cb2..0000000000 --- a/sources/tech/20171204 How To Know What A Command Or Program Will Exactly Do Before Executing It.md +++ /dev/null @@ -1,145 +0,0 @@ -translating by imquanquan - -How To Know What A Command Or Program Will Exactly Do Before Executing It -====== -Ever wondered what a Unix command will do before executing it? Not everyone knows what a particular command or program will do. Of course, you can check it with [Explainshell][2]. You need to copy/paste the command in Explainshell website and it let you know what each part of a Linux command does. However, it is not necessary. Now, we can easily know what a command or program will exactly do before executing it, right from the Terminal. Say hello to “maybe”, a simple tool that allows you to run a command and see what it does to your files without actually doing it! After reviewing the output listed, you can then decide whether you really want to run it or not. - -#### How “maybe” works? - -According to the developer, - -> “maybe” runs processes under the control of ptrace with the help of python-ptrace library. When it intercepts a system call that is about to make changes to the file system, it logs that call, and then modifies CPU registers to both redirect the call to an invalid syscall ID (effectively turning it into a no-op) and set the return value of that no-op call to one indicating success of the original call. As a result, the process believes that everything it is trying to do is actually happening, when in reality nothing is. - -Warning: You should be very very careful when using this utility in a production system or in any systems you care about. It can still do serious damages, because it will block only a handful of syscalls. - -#### Installing “maybe” - -Make sure you have installed pip in your Linux system. If not, install it as shown below depending upon the distribution you use. - -On Arch Linux and its derivatives like Antergos, Manjaro Linux, install pip using the following command: - -``` -sudo pacman -S python-pip -``` - -On RHEL, CentOS: - -``` -sudo yum install epel-release -``` - -``` -sudo yum install python-pip -``` - -On Fedora: - -``` -sudo dnf install epel-release -``` - -``` -sudo dnf install python-pip -``` - -On Debian, Ubuntu, Linux Mint: - -``` -sudo apt-get install python-pip -``` - -On SUSE, openSUSE: - -``` -sudo zypper install python-pip -``` - -Once pip installed, run the following command to install “maybe”. - -``` -sudo pip install maybe -``` - -#### Know What A Command Or Program Will Exactly Do Before Executing It - -Usage is absolutely easy! Just add “maybe” in front of a command that you want to execute. - -Allow me to show you an example. - -``` -$ maybe rm -r ostechnix/ -``` - -As you can see, I am going to delete a folder called “ostechnix” from my system. Here is the sample output. - -``` -maybe has prevented rm -r ostechnix/ from performing 5 file system operations: - - delete /home/sk/inboxer-0.4.0-x86_64.AppImage - delete /home/sk/Docker.pdf - delete /home/sk/Idhayathai Oru Nodi.mp3 - delete /home/sk/dThmLbB334_1398236878432.jpg - delete /home/sk/ostechnix - -Do you want to rerun rm -r ostechnix/ and permit these operations? [y/N] y -``` - - [![](http://www.ostechnix.com/wp-content/uploads/2017/12/maybe-1.png)][3] - -The “maybe” tool performs 5 file system operations and shows me what this command (rm -r ostechnix/) will exactly do. Now I can decide whether I should perform this operation or not. Cool, yeah? Indeed! - -Here is another example. I am going to install [Inboxer][4] desktop client for Gmail. This is what I got. - -``` -$ maybe ./inboxer-0.4.0-x86_64.AppImage -fuse: bad mount point `/tmp/.mount_inboxemDzuGV': No such file or directory -squashfuse 0.1.100 (c) 2012 Dave Vasilevsky - -Usage: /home/sk/Downloads/inboxer-0.4.0-x86_64.AppImage [options] ARCHIVE MOUNTPOINT - -FUSE options: - -d -o debug enable debug output (implies -f) - -f foreground operation - -s disable multi-threaded operation - -open dir error: No such file or directory -maybe has prevented ./inboxer-0.4.0-x86_64.AppImage from performing 1 file system operations: - -create directory /tmp/.mount_inboxemDzuGV - -Do you want to rerun ./inboxer-0.4.0-x86_64.AppImage and permit these operations? [y/N] -``` - -If it not detects any file system operations, then it will simply display a result something like below. - -For instance, I run this command to update my Arch Linux. - -``` -$ maybe sudo pacman -Syu -sudo: effective uid is not 0, is /usr/bin/sudo on a file system with the 'nosuid' option set or an NFS file system without root privileges? -maybe has not detected any file system operations from sudo pacman -Syu. -``` - -See? It didn’t detect any file system operations, so there were no warnings. This is absolutely brilliant and exactly what I was looking for. From now on, I can easily know what a command or a program will do even before executing it. I hope this will be useful to you too. More good stuffs to come. Stay tuned! - -Cheers! - -Resource: - -* [“maybe” GitHub page][1] - --------------------------------------------------------------------------------- - -via: https://www.ostechnix.com/know-command-program-will-exactly-executing/ - -作者：[SK][a] -译者：[译者ID](https://github.com/译者ID) -校对：[校对者ID](https://github.com/校对者ID) - -本文由 [LCTT](https://github.com/LCTT/TranslateProject) 原创编译，[Linux中国](https://linux.cn/) 荣誉推出 - -[a]:https://www.ostechnix.com/author/sk/ -[1]:https://github.com/p-e-w/maybe -[2]:https://www.ostechnix.com/explainshell-find-part-linux-command/ -[3]:http://www.ostechnix.com/wp-content/uploads/2017/12/maybe-1.png -[4]:https://www.ostechnix.com/inboxer-unofficial-google-inbox-desktop-client/ diff --git a/translated/tech/20171204 How To Know What A Command Or Program Will Exactly Do Before Executing It.md b/translated/tech/20171204 How To Know What A Command Or Program Will Exactly Do Before Executing It.md new file mode 100644 index 0000000000..5123c87df9 --- /dev/null +++ b/translated/tech/20171204 How To Know What A Command Or Program Will Exactly Do Before Executing It.md @@ -0,0 +1,143 @@ +如何获知一个命令或程序在执行前将会做什么 +====== + +有没有想过一个 Unix 命令在执行前将会干些什么呢？并不是每个人都会知道一个特定的命令或者程序将会做什么。当然，你可以用 [Explainshell][2] 来查看它。你可以在 Explainshell 网站中粘贴你的命令，然后它可以让你了解命令的每个部分做了什么。但是，这是没有必要的。现在，我们从终端就可以轻易地知道一个命令或者程序在执行前会做什么。 `maybe` ，一个简单的工具，它允许你运行一条命令并可以查看此命令对你的文件系统做了什么而实际上这条命令却并未执行！在查看 `maybe` 的输出列表后，你可以决定是否真的想要运行这条命令。 + +#### “maybe”是如何工作的 + +根据开发者的介绍 + +> `maybe` 利用 `python-ptrace` 库运行了一个在 `ptrace` 控制下的进程。当它截取到一个即将更改文件系统的系统调用时，它会记录该调用，然后修改 CPU 寄存器，将这个调用重定向到一个无效的系统调用 ID（将其变成一个无效操作（no-op）），并将这个无效操作（no-op）的返回值设置为有效操作的返回值。结果，这个进程认为，它所做的一切都发生了，实际上什么都没有改变。 + +警告: 在生产环境或者任何你所关心的系统里面使用这个工具时都应该小心。它仍然可能造成严重的损失，因为它只能阻止少数系统调用。 + +#### 安装 “maybe” + +确保你已经在你的 Linux 系统中已经安装了 `pip` 。如果没有，可以根据您使用的发行版，按照如下指示进行安装。 + +在 Arch Linux 及其衍生产品（如 Antergos，Manjaro Linux）上，使用以下命令安装 `pip` ： + +``` +sudo pacman -S python-pip +``` + +在 RHEL，CentOS 上： + +``` +sudo yum install epel-release +``` +``` +sudo yum install python-pip +``` + +在 Fedora 上： + +``` +sudo dnf install epel-release +``` +``` +sudo dnf install python-pip +``` + +在 Debian，Ubuntu，Linux Mint 上： + +``` +sudo apt-get install python-pip +``` + +在 SUSE, openSUSE 上: + +``` +sudo zypper install python-pip +``` + +安装 `pip` 后，运行以下命令安装 `maybe` 。 + +``` +sudo pip install maybe +``` + +#### 了解一个命令或程序在执行前会做什么 + +用法是非常简单的！只要在要执行的命令前加上 `maybe` 即可。 + +让我给你看一个例子： + +``` +$ maybe rm -r ostechnix/ +``` + +如你所看到的，我从我的系统中删除一个名为 `ostechnix` 的文件夹。下面是示例输出： + +``` +maybe has prevented rm -r ostechnix/ from performing 5 file system operations: + + delete /home/sk/inboxer-0.4.0-x86_64.AppImage + delete /home/sk/Docker.pdf + delete /home/sk/Idhayathai Oru Nodi.mp3 + delete /home/sk/dThmLbB334_1398236878432.jpg + delete /home/sk/ostechnix + +Do you want to rerun rm -r ostechnix/ and permit these operations? [y/N] y +``` + + [![](http://www.ostechnix.com/wp-content/uploads/2017/12/maybe-1.png)][3] + + + `maybe` 执行 5 个文件系统操作，并向我显示该命令（rm -r ostechnix /）究竟会做什么。现在我可以决定是否应该执行这个操作。是不是很酷呢？确实很酷！ + +这是另一个例子。我要为 Gmail 安装 Inboxer 桌面客户端。这是我得到的输出： + +``` +$ maybe ./inboxer-0.4.0-x86_64.AppImage +fuse: bad mount point `/tmp/.mount_inboxemDzuGV': No such file or directory +squashfuse 0.1.100 (c) 2012 Dave Vasilevsky + +Usage: /home/sk/Downloads/inboxer-0.4.0-x86_64.AppImage [options] ARCHIVE MOUNTPOINT + +FUSE options: + -d -o debug enable debug output (implies -f) + -f foreground operation + -s disable multi-threaded operation + +open dir error: No such file or directory +maybe has prevented ./inboxer-0.4.0-x86_64.AppImage from performing 1 file system operations: + +create directory /tmp/.mount_inboxemDzuGV + +Do you want to rerun ./inboxer-0.4.0-x86_64.AppImage and permit these operations? [y/N] +``` + +如果它没有检测到任何文件系统操作，那么它会只显示如下所示的结果。 + +例如，我运行下面这条命令来更新我的 Arch Linux。 + +``` +$ maybe sudo pacman -Syu +sudo: effective uid is not 0, is /usr/bin/sudo on a file system with the 'nosuid' option set or an NFS file system without root privileges? +maybe has not detected any file system operations from sudo pacman -Syu. +``` + +看到没？它没有检测到任何文件系统操作，所以没有任何警告。这非常棒，而且正是我所预料到的结果。从现在开始，我甚至可以在执行之前知道一个命令或一个程序将执行什么操作。我希望这对你也会有帮助。 + +Cheers! + +资源: + +* [“maybe” GitHub page][1] + +-------------------------------------------------------------------------------- + +via: https://www.ostechnix.com/know-command-program-will-exactly-executing/ + +作者：[SK][a] +译者：[imquanquan](https://github.com/imquanquan) +校对：[校对ID](https://github.com/校对ID) + +本文由 [LCTT](https://github.com/LCTT/TranslateProject) 原创编译，[Linux中国](https://linux.cn/) 荣誉推出 + +[a]:https://www.ostechnix.com/author/sk/ +[1]:https://github.com/p-e-w/maybe +[2]:https://www.ostechnix.com/explainshell-find-part-linux-command/ +[3]:http://www.ostechnix.com/wp-content/uploads/2017/12/maybe-1.png +[4]:https://www.ostechnix.com/inboxer-unofficial-google-inbox-desktop-client/