如何編寫帶有可選輸入參數的 bash 腳本？ - How to write a bash script that takes optional input arguments?

問題：

I want my script to be able to take an optional input,我希望我的腳本能夠接受一個可選的輸入，

eg currently my script is例如目前我的腳本是

#!/bin/bash
somecommand foo

but I would like it to say:但我想說：

#!/bin/bash
somecommand  [ if $1 exists, $1, else, foo ]

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解決方案：

參考一： https://en.stackoom.com/question/d9t4
參考二： https://stackoom.com/question/d9t4