参考:https://stackoverflow.com/questions/3601515/how-to-check-if-a-variable-is-set-in-bash 6、换算秒为分钟、小时 代码语言:javascript 代码运行次数:0 运行 AI代码解释 #!/bin/bash a=60100 swap_seconds () { SEC=$1 (( SEC < 60 )) && ech
--ignore-length ignore 'Content-Length' header field --header=STRING insert STRING among the headers --compression=TYPE choose compression, one of auto, gzip and none. (default: none) --max-redirect maximum redirections allowed per page --proxy-user=USER set USER as proxy username --proxy-...
The variable is not empty. These two examples are similar to the previous examples, but we used the -n operator here. Unlike the -z option, the -n option is also a unary test operator used to determine the length of the specified variable, whether it is zero or not. If the length...
echo"the variable X is not the empty string" fi 运行这个脚本,输出如下: the variable X is not the empty string 为何?这是因为shell将$X展开为空字符串,表达式[-n]返回真值(因为改表达式没有提供参数)。再看这个脚本: 1 2 3 4 5 #!/bin/bash X="" if[ -n"$X"];then# -n 用来检查变量是...
| ${VAR:OFFSET:LENGTH} | 获得从OFFSET字符之后LENGTH个字符的字符串. (${VAR:10:10}: 获得从第10个字符到第20个字符的字符串) | ${VAR:: OFFSET} | 从变量中获取前OFFSET个字符. | ${VAR:: -OFFSET} | 从变量中移除前OFFSET个字符. | ${VAR: -OFFSET} | 从变量中获取最后OFFSET个字符. |...
Bash has a few conditional expressions, of which you can use one to check if a variable is empty or not. That is the-zoperator. Using the-zoperator followed by a variable will result in trueif the variable is empty. The condition will evaluate to false if the variable is not empty. ...
kubernetes 即使不满足条件也执行函数体时执行Bash [重复]此if条件 如果“$status”！=“正在运行”||...
random_select.sh - selects one of given args at random. Useful for sampling, running randomized subsets of large test suites etc. random_number.sh - prints a random integer between two integer arguments (inclusive) random_string.sh - prints a random alphanumeric string of a given length shie...
You can assign data to a variable using the equals sign (=). The data you store in a variable can either be a string or a number. Let’s create a variable now on the command line: chapter_number=5 The variable name is on the left hand side of the equals sign, and the data whic...
api-version=2023-01-01' cli.azure.cli.core.sdk.policies: Request method: 'POST' cli.azure.cli.core.sdk.policies: Request headers: cli.azure.cli.core.sdk.policies: 'Content-Type': 'application/json' cli.azure.cli.core.sdk.policies: 'Content-Length': '73' cli.azure.cli.core.sdk....