Stores the exit status in the variable 'exit_status'. Print the exit status code: echo "Exit status code: $exit_status" Prints the exit status code along with a descriptive message. $exit_status is the value of the exit status code captured in step 3.2...
The underscore variable is set at shell startup and contains the absolute file name of the shell or script being executed as passed in the argument list. Subsequently, it expands to the last argument to the previous command, after expansion. It is also set to the full pathname of each comm...
variable_int=100 # 访问变量, 在变量前添加 $ 符号, 该符号的目的是告诉 Shell 访问变量的值而非变量名本身 # echo 是 Linux 终端命令, 主要将文本, 变量, 和特殊字符输出到标准输出 ( 通常是终端屏幕 ) echo $variable_str echo $variable_int 实际上访问变量时需使用 "" 防止通配符扩展和单词拆分。① ...
FOR循环以for [variable name] in [sequence]的语法开头,然后是下一行的do。在for之后立即定义的变量名将在循环内部接受一个值,该值对应于在in之后提供的序列中的一个元素,从序列的第一个元素开始,然后是每个后续元素。有效序列包括大括号展开、字符串的显式列表、数组和命令替换。在这个例子中,我们使用了大括号...
The special variable $? returns the exit status of the last executed command:date &> /dev/nullecho $?CopyCopy The date command completed successfully, and the exit code is zero:0 Copy If you try to run ls on a nonexisting directory the exit code will be non-zero:ls...
While ShellCheck is mostly intended for interactive use, it can easily be added to builds or test suites. It makes canonical use of exit codes, so you can just add ashellcheckcommand as part of the process. For example, in a Makefile: ...
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 )) && echo -e "持续时间: $SEC秒\c" (( SEC >= 60...
case"variable"in"pattern1"Command … ;;"pattern2"Command … ;;"pattern2"Command … ;;esac 1. 注意: 条件语句最后总会包含一个空格和右括号); 条件语句后的命令以两个分号;;结束,其前面的空格可有可没有; case 语句 以esac结尾(与 case 相反)。
echo"<the_command> could not be found"exit fi 对于Bash 特定环境: 代码语言:javascript 代码运行次数:0 运行 AI代码解释 hash<the_command># 用于常规命令。或 type<the_command># 检查内置项和关键字 避免使用 which。它是一个外部进程,相对而言 hash、type 或 command 这样的内置程序执行效率更高,你还可...
Code: #!/bin/bash # Shebang line: Indicates the path to the shell interpreter (in this case, bash) # Storing the output of the date command in a variable currentDateTime=$(date) # Printing the value of the variable echo "Current date and time: $currentDateTime" ...