其他¶
\[\sigma_\mathrm{mean} = \frac{\sigma}{\sqrt{N}}\]
\[\begin{split}\begin{bmatrix}
1 & 3\\
-2 & 0
\end{bmatrix}
\begin{bmatrix}
-1 \\
2
\end{bmatrix} =
\begin{bmatrix}
5 \\
2
\end{bmatrix}\end{split}\]
windows 计算 MD5 SHA1 SHA256
> certutil -hashfile D:\filename.txt MD5
> certutil -hashfile D:\filename.txt SHA1
> certutil -hashfile D:\filename.txt SHA256
系统常见问题¶
- Ubuntu
-
# 安装ccsm sudo apt-get install compizconfig-settings-manager # 启动ccsm : General -> OpenGL -> disable “Sync To VBlank” ccsm
-
- Windows镜像下载地址
- https://msdn.itellyou.cn/
- qbittorrent
- http://www.qbittorrent.org/
OBS Studio¶
搭建RTMP服务器
Docker
# https://hub.docker.com/r/jasonrivers/nginx-rtmp/
$ sudo docker run -d -p 1935:1935 -p 8088:8080 --rm jasonrivers/nginx-rtmp
# or
# https://github.com/alfg/docker-nginx-rtmp
$ sudo docker run -d -p 1935:1935 -p 8080:80 --rm alfg/nginx-rtmp
windows
开源许可证¶
http://www.ruanyifeng.com/blog/2011/05/how_to_choose_free_software_licenses.html
http://www.ruanyifeng.com/blog/2011/05/how_to_choose_free_software_licenses.html
other¶
SPAW 分区¶
Linux系统swappiness参数在内存与交换分区之间优化作用
Linux VPS的使用过程中，SWAP交换分区是一个很重要系统缓存分区。他是在内存不够用的情况下，从硬盘中临时分出一部分空间系统当做内存使用。但是，如果SWAP的占用超过30%的时候，系统的性能就会受到影响，这时候就要刷新SWAP。
# 可以执行命令刷新一次SWAP（将SWAP里的数据转储回内存，并清空SWAP里的数据）
$ sudo swapoff -a && sudo swapon -a
$ cat /proc/sys/vm/swappiness # 查看
$ sysctl -q vm.swappiness # 查看当前设置
# 临时设置
$ sudo sysctl vm.swappiness=10
# 永久设置
$ sudo echo "vm.swappiness=10" >> /etc/sysctl.conf
$ sysctl -p # 激活
CenterOS¶
检查某服务是否开机启动
# chkconfig dnsmasq开启/禁止 某服务开机启动
# chkconfig dnsmasq on/off # systemctl enable/disable dnsmasq
启动/停止/重启 某服务
# systemctl start/stop/restart dnsmasq
amixer¶
- 查看:
$ sudo alsamixer
$ sudo amixer -D pulse
$ sudo amixer scontrols # 查看,哪些选择可以控制
- 声音设置
$ amixer -D pulse sset "Master" on
$ amixer -D pulse sset "Master" off // 静音
$ amixer set "Master" 100%
$ amixer set "PCM" 94% # 6100u 华科 噪音
- 录音设置
$ amixer set "Capture" 100%
$ amixer set "Front Mic Boost" 53%
$ amixer set "Rear Mic Boost" 53%
$ sudo apt-get install alsa-base alsa-utils alsa-oss alsa-tools
# 1. 如果默认声卡不是需要的
# 在home目录添加.asoundrc文件
$ sudo tee $HOME/.asoundrc <<-'EOF'
defaults.ctl.card 1 defaults.pcm.card 1
EOF
# 数字1代表声卡序号
# 可以通过以下指令查看
$ cat /proc/asound/cards
# 2. alsamixer调节声音
# Master和PCM是必须打开的。
# Master和PCM声道默认是静音的，标记是MM，用左右方向键选择，按M来修改为OO就是开启，上下键调节音量大小。
# 配置好之后执行：
$ alsactl store # 保存配置, 配置会保存在/var/lib/alsa/asound.state
nmcli命令¶
2.3.使用 NETWORKMANAGER 命令行工具 NMCLI
$ nmcli help
$ nmcli c help
$ nmcli con show
$ nmcli dev show eth0
rmp and yum¶
查询含有 *rdma.so 的rpm 包¶
yum provides *rdma.so
- Fedora 开启SSH服务
- https://my.oschina.net/atttx123/blog/58100
ubutnu 源制作¶
https://gist.github.com/awesomebytes/ce0643c1ddead589ab06e2a1e4c5861b
- Requirements
- Python (I used 2.7).
- dpkg-scanpackages: sudo apt-get install dpkg-dev
- gzip: sudo apt-get install gzip
- Create your debian hosting folder structure
mkdir simple_debian_repo cd simple_debian_repo mkdir debian- Add your .deb files to the debian folder
cp my_awesome_thing.deb simple_debian_repo/debian
- Create Packages.gz file
# You'll need to do this every time you add/update a .deb. dpkg-scanpackages debian /dev/null | gzip -9c > debian/Packages.gz
You'll get an output similar to
dpkg-scanpackages: warning: Packages in archive but missing from override file: dpkg-scanpackages: warning: my_awesome_thing.deb dpkg-scanpackages: info: Wrote 1 entries to output Packages file.
- Run a webserver to host it
cd simple_debian_repo/ python -m SimpleHTTPServer 8000
- Configure any machine to point to your new debian repository
tee /etc/apt/sources.list <<-"EOF" deb [trusted=yes] http://127.0.0.1:8000 debian/ EOF apt-get update apt-cache search "deb包“
- Note:
that the packages will be non authenticated, so if you want to stop having warnings you'll need to add the [trusted=yes]
ubuntu 好用的工具¶
# Indicator Stickynotes - Ubuntu 桌面便签小工具
sudo add-apt-repository ppa:umang/indicator-stickynotes
sudo apt-get update
sudo apt-get install indicator-stickynotes
tty终端中显示和输入中文¶
- https://blog.csdn.net/maybe_frank/article/details/53371201
- https://fooyou.github.io/document/2015/11/30/fbterm-display-and-input-Chinese-in-tty.html
$ sudo apt-get install fbterm
$ sudo fbterm
问题¶
Apache2¶
重启Apache2出现：
Could not reliably determine the server's fully qualified domain name, using 127.0.1.1 for ServerName.问题
在/etc/apache2/apache2.conf文件最后加上：
# Server Name
ServerName localhost
# centos 目录或文件名中文显示
# vim /etc/httpd/conf/httpd.conf
AddDefaultCharset UTF-8
IndexOptions Charset=GBK
插入youku视频
插入github 视频
插入gitliab 视频
插入百度云盘
- remote-viewer
--hotkeys=release-cursor="" # 屏蔽 ctrl+alt