在Linux中,if else语句中可以使用逻辑运算符来组合多个条件。常用的逻辑运算符包括: 逻辑与(AND):用"&&"表示,表示只有所有条件都为真时,整个条件才为真。 逻辑或(OR):用"||"表示,表示只要有一个条件为真时,整个条件就为真。 逻辑非(NOT):用"!"表示,表示对条件进行取反。 例如,以下是一个if else语句中...
If recollecting were forgetting, 我将不再回忆. Then I remember not. 如果忘却就是记住, And if forgetting, recollecting, 我多么接近于忘却. How near I had forgot. 如果相思,是娱乐, And if to miss, were merry, 而哀悼,是喜悦, And to mourn, were gay, 那些手指何等欢快,今天, How very blithe...
if [[ ( $num -lt 10 ) && ( $num%2 -eq 0 ) ]]; thenecho "Even Number"elseecho "Odd Number"fi AND运算符由&&符号表示。 11.使用OR运算符 OR运算符是另一个关键的构造,它允许我们在脚本中实现复杂、健壮的编程逻辑。与AND相反,当OR运算符的任一操作数为真时,由OR运算符组成的语句返回真。仅...
-a逻辑AND,两个条件都需为true。例如:[ var1 -a var2 ] -o逻辑OR,两个条件中任一个条件都为true。例如:[ var1 -o var2 ] !逻辑NOT,取反条件例如:[ ! "var1" = "var2" ] 4. if语句的例子 来看一个if语句的例子,来演示中括号在表达式中的用法: bash #!/bin/bash num1=10 num2=20 if ...
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[ ARG1 OP ARG2 ] “OP” is one of-eq, -ne, -lt, -le, -gt or-ge. These arithmetic binary operators return true if “ARG1” is equal to, not equal to, less than, less than or equal to, greater than, or greater than or equal to “ARG2”, respectively. “ARG1” and “ARG2...
ifconfig 显示或者设置网络设备 sudo 以系统管理员的身份执行指令,类似于windows CMD,右键选择"以管理员身份运行“” rm 删除文件 cal 日历 df 查看磁盘使用情况 cp 复制文件 date 日期 stat 显示文件或者文件系统的状态 touch 更新文件的访问时间和修改时间,如果不存在,则创建之 bc 计算器 linux命令的常识: (1)...
If one or more files are specified, sync only them, or their containing file systems. -d, --data sync only file data, no unneeded metadata -f, --file-system sync the file systems that contain the files --help display this help and exit ...
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2017: "Dirty COW and why lying is bad even if you are the Linux kernel" [article] [CVE-2016-5195]2017: "NDAY-2017-0103: Arbitrary kernel write in sys_oabi_epoll_wait" by Zuk Avraham [article] [CVE-2016-3857]2017: "NDAY-2017-0106: Elevation of Privilege in NVIDIA nvhost-vic ...