Linux cd命令:切换目录

Linux学习1 Linux的一些基本操作 阅读详情

cd 命令,是 Change Directory 的缩写,用来切换工作目录。

 

Linux 命令按照来源方式,可分为两种,分别是 Shell 内置命令和外部命令。所谓 Shell 内置命令,就是 Shell 自带的命令,这些命令是没有执行文件的;而外部命令就是由程序员单独开发的,是命令,所以会有命令的执行文件。Linux 中的绝大多数命令是外部命令,而 cd 命令是一个典型的 Shell 内置命令,所以 cd 命令没有执行文件所在路径。

cd 命令的基本格式如下:

[root@localhost ~]# cd [相对路径或绝对路径]

除此之外,cd 命令后面可以跟一些特殊符号,表达固定的含义,如表 1 所示:

表 1 cd 命令的特殊符号
特殊符号 作 用
~ 代表当前登录用户的主目录
~用户名 表示切换至指定用户的主目录
– 代表上次所在目录
. 代表当前目录
.. 代表上级目录

它们的用法分别是:

  1. [root@localhost vbird]# cd ~
    #表示回到自己的主目录,对于 root 用户,其主目录为 /root
    [root@localhost ~]# cd
    #没有加上任何路径,也代表回到当前登录用户的主目录
    [root@localhost ~]# cd ~vbird
    #代表切换到 vbird 这个用户的主目录,亦即 /home/vbird

  2. <
实战 | OpenCV实现扫描文本矫正应用与实现详解(附源码) 导读 本文主要介绍使用OpenCV对扫描文本矫正的应用实例及详细实现步骤。 背景介绍 在使用打印机或扫描仪扫描文档时,由于摆放位置差异难免造成扫描文档的倾斜。本文将使用OpenCV将倾斜的文档矫正水平并去除黑边。 实现步骤 本文只针对包含大部分文字的文档做倾斜矫正,思路来源是大部分文字倾斜后同一行的也在同一条直线,通过拟合直线计算文本倾斜角度,然后旋转来实现文本倾斜矫正。 详细步骤: ①加载倾斜图像 ②灰度转换+腐蚀+膨胀 ③Canny边缘检测 + 霍夫线变换检测直线 ... 阅读详情

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深度学习工具包 DeepLearningToolbox

深度学习工具包Deprecation notice.-----This toolbox is outdated and no longer maintained.There are much better tools available for deep learning than this toolbox, e.g. [Theano](http://deeplearning.net/software/theano/), [torch](http://torch.ch/) or [tensorflow](http://www.tensorflow.org/)I would suggest you use one of the tools mentioned above rather than use this toolbox.Best, Rasmus.DeepLearnToolbox================A Matlab toolbox for Deep Learning.Deep Learning is a new subfield of machine learning that focuses on learning deep hierarchical models of data.It is inspired by the human brain's apparent deep (layered, hierarchical) architecture.A good overview of the theory of Deep Learning theory is[Learning Deep Architectures for AI](http://www.iro.umontreal.ca/~bengioy/papers/ftml_book.pdf)For a more informal introduction, see the following videos by Geoffrey Hinton and Andrew Ng.* [The Next Generation of Neural Networks](http://www.youtube.com/watch?v=AyzOUbkUf3M) (Hinton, 2007)* [Recent Developments in Deep Learning](http://www.youtube.com/watch?v=VdIURAu1-aU) (Hinton, 2010)* [Unsupervised Feature Learning and Deep Learning](http://www.youtube.com/watch?v=ZmNOAtZIgIk) (Ng, 2011)If you use this toolbox in your research please cite [Prediction as a candidate for learning deep hierarchical models of data](http://www2.imm.dtu.dk/pubdb/views/publication_details.php?id=6284)```@MASTERSTHESIS\{IMM2012-06284, author = "R. 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nn.output = 'softmax'; % use softmax outputopts.numepochs = 5; % Number of full sweeps through dataopts.batchsize = 1000; % Take a mean gradient step over this many samplesopts.plot = 1; % enable plottingnn = nntrain(nn, tx, ty, opts, vx, vy); % nntrain takes validation set as last two arguments (optionally)[er, bad] = nntest(nn, test_x, test_y);assert(er < 0.1, 'Too big error');```[![Bitdeli Badge](https://d2weczhvl823v0.cloudfront.net/rasmusbergpalm/deeplearntoolbox/trend.png)](https://bitdeli.com/free "Bitdeli Badge")

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