• 1.输入命令： [root@master ~]# crontab -e 2.添加： */5 * * * * /usr/share/nginx/spark_run_nginx_log.sh 2&>1 >> /usr/share/nginx/crontab_spark_run_nginx.log 3.等待验证： [root@master ~]# cd /usr/...
• 本文先介绍两个框架的组件共性和不兼容的地方，再介绍react-to-vue的使用和原理,需要的朋友可以参考下
• 无聊些了个简单例程
• 直接执行这两个命令即可： sudo update-alternatives --install /usr/bin/python python /usr/bin/python2 100 sudo update-alternatives --install /usr/bin/python python /usr/bin/python3 150 如果要切换到...
• 主要介绍了Linux本机与服务器文件互传及Linux服务器文件上传下载命令写法,需要的朋友可以参考下
• CMD执行多条命令 可以用这三种分开 & && || 用 & 隔开，1命令&2命令。 用法是前后命令不管是可否运行都会运行下去，就是运行1命令，运行2命令。 用 && 隔开，1命令&&2命令。 ...
CMD执行多条命令 可以用这三种分开 & && ||
用 & 隔开，命令1 & 命令2。 用法是前后命令不管是可否运行都会运行下去，就是运行1命令，运行2命令。
用 && 隔开，命令1 && 命令2。 用法是前面的命令运行成功才运行后面的命令，就是运行1命令没出错、运行成功才运行2命令。
用 || 隔开，命令1 || 命令2。 用法是前面的命令运行成功才运行后面的命令，就是运行1命令出错、运行不成功才运行2命令。
|管道符
||代表上一句执行失败
&&代表上一句执行成功
&连接符

echo 123 | findstr "12"

xcopy 123.txt d:\ && (echo ok ) || (echo error)

@echo off&cls

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• liunx命令，一些liunx普通命令的用法和格式
• windows下的各种批处理命令写法。。
• shell脚本中的命令需加反引号
shell脚本中的命令需加反引号
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• Azkaban定时命令写法指南Cron Trigger Tutorial CronTrigger TutorialCronTrigger TutorialIntroductionFormatSpecial charactersExamplesNotesIntroductioncron is a UNIX tool that has been around for a long ...
Azkaban定时命令写法指南
Cron Trigger Tutorial

CronTrigger Tutorial

CronTrigger Tutorial
IntroductionFormatSpecial charactersExamplesNotes

Introduction
cron is a UNIX tool that has been around for a long time, so its scheduling capabilities are powerful and proven. The CronTrigger class is based on the scheduling capabilities of cron.
CronTrigger uses “cron expressions”, which are able to create firing schedules such as: “At 8:00am every Monday through Friday” or “At 1:30am every last Friday of the month”.
Cron expressions are powerful, but can be pretty confusing. This tutorial aims to take some of the mystery out of creating a cron expression, giving users a resource which they can visit before having to ask in a forum or mailing list.
Format
A cron expression is a string comprised of 6 or 7 fields separated by white space. Fields can contain any of the allowed values, along with various combinations of the allowed special characters for that field. The fields are as follows:
Field NameMandatoryAllowed ValuesAllowed Special CharactersSecondsYES0-59, - * /MinutesYES0-59, - * /HoursYES0-23, - * /Day of monthYES1-31, - * ? / L WMonthYES1-12 or JAN-DEC, - * /Day of weekYES1-7 or SUN-SAT, - * ? / L #YearNOempty, 1970-2099, - * /
So cron expressions can be as simple as this: * * * * ? *
or more complex, like this: 0/5 14,18,3-39,52 * ? JAN,MAR,SEP MON-FRI 2002-2010
Special characters
* (“all values”) - used to select all values within a field. For example, “” in the minute field means *“every minute”.? (“no specific value”) - useful when you need to specify something in one of the two fields in which the character is allowed, but not the other. For example, if I want my trigger to fire on a particular day of the month (say, the 10th), but don’t care what day of the week that happens to be, I would put “10” in the day-of-month field, and “?” in the day-of-week field. See the examples below for clarification.- - used to specify ranges. For example, “10-12” in the hour field means “the hours 10, 11 and 12”., - used to specify additional values. For example, “MON,WED,FRI” in the day-of-week field means “the days Monday, Wednesday, and Friday”./ - used to specify increments. For example, “0/15” in the seconds field means “the seconds 0, 15, 30, and 45”. And “5/15” in the seconds field means “the seconds 5, 20, 35, and 50”. You can also specify ‘/’ after the ‘’ character - in this case ‘’ is equivalent to having ‘0’ before the ‘/’. ‘1/3’ in the day-of-month field means “fire every 3 days starting on the first day of the month”.L (“last”) - has different meaning in each of the two fields in which it is allowed. For example, the value “L” in the day-of-month field means “the last day of the month” - day 31 for January, day 28 for February on non-leap years. If used in the day-of-week field by itself, it simply means “7” or “SAT”. But if used in the day-of-week field after another value, it means “the last xxx day of the month” - for example “6L” means “the last friday of the month”. You can also specify an offset from the last day of the month, such as “L-3” which would mean the third-to-last day of the calendar month. When using the ‘L’ option, it is important not to specify lists, or ranges of values, as you’ll get confusing/unexpected results.W (“weekday”) - used to specify the weekday (Monday-Friday) nearest the given day. As an example, if you were to specify “15W” as the value for the day-of-month field, the meaning is: “the nearest weekday to the 15th of the month”. So if the 15th is a Saturday, the trigger will fire on Friday the 14th. If the 15th is a Sunday, the trigger will fire on Monday the 16th. If the 15th is a Tuesday, then it will fire on Tuesday the 15th. However if you specify “1W” as the value for day-of-month, and the 1st is a Saturday, the trigger will fire on Monday the 3rd, as it will not ‘jump’ over the boundary of a month’s days. The ‘W’ character can only be specified when the day-of-month is a single day, not a range or list of days.

The 'L' and 'W' characters can also be combined in the day-of-month field to yield 'LW', which translates to *"last weekday of the month"*.

# - used to specify “the nth” XXX day of the month. For example, the value of “6#3” in the day-of-week field means “the third Friday of the month” (day 6 = Friday and “#3” = the 3rd one in the month). Other examples: “2#1” = the first Monday of the month and “4#5” = the fifth Wednesday of the month. Note that if you specify “#5” and there is not 5 of the given day-of-week in the month, then no firing will occur that month.

The legal characters and the names of months and days of the week are not case sensitive.

MON
is the same as

mon.

Examples
Here are some full examples:
**Expression****Meaning**0 0 12 * * ?Fire at 12pm (noon) every day0 15 10 ? * *Fire at 10:15am every day0 15 10 * * ?Fire at 10:15am every day0 15 10 * * ? *Fire at 10:15am every day0 15 10 * * ? 2005Fire at 10:15am every day during the year 20050 * 14 * * ?Fire every minute starting at 2pm and ending at 2:59pm, every day0 0/5 14 * * ?Fire every 5 minutes starting at 2pm and ending at 2:55pm, every day0 0/5 14,18 * * ?Fire every 5 minutes starting at 2pm and ending at 2:55pm, AND fire every 5 minutes starting at 6pm and ending at 6:55pm, every day0 0-5 14 * * ?Fire every minute starting at 2pm and ending at 2:05pm, every day0 10,44 14 ? 3 WEDFire at 2:10pm and at 2:44pm every Wednesday in the month of March.0 15 10 ? * MON-FRIFire at 10:15am every Monday, Tuesday, Wednesday, Thursday and Friday0 15 10 15 * ?Fire at 10:15am on the 15th day of every month0 15 10 L * ?Fire at 10:15am on the last day of every month0 15 10 L-2 * ?Fire at 10:15am on the 2nd-to-last last day of every month0 15 10 ? * 6LFire at 10:15am on the last Friday of every month0 15 10 ? * 6LFire at 10:15am on the last Friday of every month0 15 10 ? * 6L 2002-2005Fire at 10:15am on every last friday of every month during the years 2002, 2003, 2004 and 20050 15 10 ? * 6#3Fire at 10:15am on the third Friday of every month0 0 12 1/5 * ?Fire at 12pm (noon) every 5 days every month, starting on the first day of the month.0 11 11 11 11 ?Fire every November 11th at 11:11am.

Pay attention to the effects of '?' and '*' in the day-of-week and day-of-month fields!

Notes
Support for specifying both a day-of-week and a day-of-month value is not complete (you must currently use the ‘?’ character in one of these fields).Be careful when setting fire times between the hours of the morning when “daylight savings” changes occur in your locale (for US locales, this would typically be the hour before and after 2:00 AM - because the time shift can cause a skip or a repeat depending on whether the time moves back or jumps forward. You may find this wikipedia entry helpful in determining the specifics to your locale:https://secure.wikimedia.org/wikipedia/en/wiki/Daylight_saving_time_around_the_world
参考：http://www.quartz-scheduler.org/documentation/quartz-2.x/tutorials/crontrigger.html
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• Android 虚拟机 启动 bat 命令写法 找到虚拟机所在的文件路径 搜索 emulator.exe 找到Android\Sdk\emulator 文件的路径,下面的示例是我们需要的，如果文件名中含有空格需要用双引号包起来 D:“Program Files”\...
Android 虚拟机 启动 bat 命令写法
找到虚拟机所在的文件路径
搜索 emulator.exe 找到Android\Sdk\emulator 文件的路径,下面的示例是我们需要的，如果文件名中含有空格需要用双引号包起来

D:“Program Files”\Android\Sdk\emulator\emulator.exe

打开Androidstudio 找到AVDManager 并打开，复制虚拟机的名字（如果名字中包含空格，要将空格改成下划线）。 最后得到我们要的结果

D:“Program Files”\Android\Sdk\emulator\emulator.exe -netdelay none -netspeed full -avd Nexus_5X_API_27

vs code 启动虚拟机方法

仅为flutter项目做展示！

打开 flutter项目，在vscode 右下角会显示没有设备，点击一下，就会有启动选项

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• 主要介绍了使用命令对象代替switch语句的写法示例,JS规范里面是禁止使用switch语句的,使用命令对象可以完美的解决这个问题,需要的朋友可以参考下
• mysql全文搜索,sql的写法: MATCH (col1,col2,…) AGAINST (expr [IN BOOLEAN MODE | WITH QUERY EXPANSION]) 比如: SELECT * FROM articles WHERE MATCH (title,body) AGAINST (‘database’); MATCH()函数对于一个...
• 重启命令： 1、reboot 2、shutdown -r now 立刻重启(root用户使用) 3、shutdown -r 10 过10分钟自动重启(root用户使用) 4、shutdown -r 20:35 在时间为20:35时候重启(root用户使用) 关机命令： 1、halt 立刻关机 2...
• 本篇文章主要介绍了Linux中拷贝 cp命令中拷贝所有的写法，具有一定的参考价值，感兴趣的小伙伴们可以参考一下。
• 非常详细！！
• 例子：注意空格哦 if [[ -f "/home/01" ]]; then echo "ok"; else echo "no"; fi
• ## nohup命令详解

万次阅读 2019-05-22 00:12:56
nohup 命令运行由 Command参数和任何相关的 Arg参数指定的命令，忽略所有挂断（SIGHUP）信号。在注销后使用 nohup 命令运行后台中的程序。要运行后台中的 nohup 命令，添加 & （ 表示“and”的符号）到命令的...
• 《几种简单的.bat批处理文件的写法及举例》 一、echo off.bat批处理 echo off.bat命令如下，我们做好后用记事本保存为"echo.bat"后缀文件。 @echo off echo"欢迎来到非常BAT!" pause 双击后会出现下面CMD...
• 功能：route命令是操作，维护路由表的重要工具 1》route print 查看路由表 2》route add 增加一条路由记录 例如：route add 1.1.0.0 mask 255.255.0.0 10.110.41.20 metric 5 3》route delete 删除一条路由记录 ...
• 在Linux shell命令行提示符下输入命令，当系统接受、解释并执行你的命令，并且向你提供shell脚本和自动任务执行的编译模块。Linux shell命令包含了一些功能强大的工具和方便之处。如果你是经常要用到命令行的用户，...
• sed -i '/#PermitRootLogin/s/#//g' /etc...这种写法很有用，因为我们很多时候不适合直接用s命令上来就全文替换，而是只替换某一行，此时就可以这样写代码 转载于:https://www.cnblogs.com/super119/archive/2010/12...
• 控制部件通过控制线向执行部件发出各种控制命令，通常这种控制命令叫做微命令，是最小单位，组成微指令 。 在机器的一个CPU周期中，一组实现一定操作功能的微命令的组合，构成一条微指令 事实上一条机器指令的功能是...
• 在c++中一语句太长，为了便于阅读会分成多行来写，在字符串换行处加一个反斜杠’\’，下一行前不能有空格或者Tab键；举例如下：char chstr2[] = "abcabc\ abcabc";而在cmd脚本中实现的同样功能的连接符是“^”。...
• 》路由器的静态路由配置  #静态路由的应用实例  在网络设计中，静态路由广泛得应用与点到点的... 在全局配置模式下，使用”ip route”命令配置静态路由，使用”noip route”命令删除静态路由配置。  命令格式

...