select 是个无限循环,因此要记住用break 命令退出循环,或用exit 命令终止脚本。也可以按ctrl+c 退出循环。 select 经常和case 联合使用 与for 循环类似,可以省略in list ,此时使用位置参量 select示例: 示例2 函数function介绍 1)函数function是由若干条shell命令组成的语句块,实现代码重用和模块化编程。 2)它与she...
Return is a bash builtin function that causes to update the exit status specified by n. Return is intended to be used only for signaling errors, not for returning the results of function. If used: inside a function. Return value specified by n.
通过利用“os”模块、“psutil”库和“子流程”模块，我们将为自己配备一个多功能工具包来解决这项势在...
function finish { # 重启服务 sudo service mongdb start } trap finish EXIT # 关闭 mongod 服务 sudo service mongdb stop # (如果 mongod 配置了 fork ,比如 replica set ,你可能需要执行 “sudo killall --wait /usr/bin/mongod”) 控制开销 有一种情况特别能体现 EXIT trap 的价值:如果你的脚本运...
status() {if[ -e $lockfile];thenecho"The service $prog is running."elseecho"The service $prog is not running."fi}case$1instart) start ;; stop) stop ;; restart) restart ;; status) status ;;*)echo"Usage: $prog {start|stop|restart|status}"exit1;;esac ...
Using functions in bash scripting comes with two benefits: 1. A function is read directly into the shell's memory and stored for later use. Since computer memory is not an issue nowadays, using functions is faster than repeating code. ...
Bash函数中的返回值尽管bash有一条return语句，但您只能用它指定函数的自身exit状态（介于0和之间的值255...
" local error_line="$1" echo "Error occurred at line $error_line with exit code $error_code" # 显示调用堆栈 local i=0 while caller $i; do ((i++)) done exit $error_code } # 设置错误处理函数 trap 'handle_error $LINENO' ERR func1 上述代码中,我们定义了四个函数:func1、func2、...
1. for i in $(ls *.mp3) Bash 写循环代码的时候,确实比较容易犯下面的错误: for i in $(ls *.mp3); do # 错误! some command $i # 错误! done for i in $(ls) # 错误! for i in `ls` # 错误! for i in $(find . -type f) # 错误!
A bash function can return a value via its exit status after execution. By default, a function returns the exit code from the last executed command inside the function. It will stop the function execution once it is called. You can use the return builtin command to return an arbitrary numb...