shell script 布林運算順序

一般寫程式都有 not and or 順序去做運算
但今天我發現 shell script 運算結果跟(別的)程式結果不太一樣
查了一下發現，shell script 是由左往右

這邊就很清楚，說shell 布林運算都是左到右

In many computer languages, operators with the same precedence are left-associative. That is, in the absence of grouping structures, leftmost operations are executed first. Bash is no exception to this rule.
This is important because, in Bash, && and || have the same precedence.
So what happens in your example is that the leftmost operation (||) is carried out first:
…
bash - Precedence of the shell logical operators &&, || - Unix & Linux Stack Exchange

if 多條件 boolean 寫法

可用 && , ||

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if [ -e $xxxx ] || [ -e $oooo ] && [ -e $dddd ] && [  -e $eeee ]
then
    ....
else
    ....
fi

可用 bash [[ 和 ]]調整順序

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if [ -e $dddd ] && [  -e $eeee ] && [[ -e $xxxx  ||  -e $oooo ]] 
then
    ....
else
    ....
fi

發現 sh 也可以用 ( )

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if [ -e $dddd ] && [  -e $eeee ] && ([ -e $xxxx ] || [ -e $oooo ]) 
then
    ....
else
    ....
fi

還可以這樣用-o -a

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if [ -e $dddd ] && [  -e $eeee ] && [ -e $xxxx -o -e $oooo ]
then
    ....
else
    ....
fi

參考連結:

Bash if statement with multiple conditions throws an error - Stack Overflow
Multiple conditions in if statement shell script - Stack Overflow
shell - Boolean operators ( &&, -a, ||, -o ) in Bash - Stack Overflow
bash - How to represent multiple conditions in a shell if statement? - Stack Overflow

彩蛋

Vagrant介绍-从使用到放弃再到掌握完全指南 - 宋净超的博客|Cloud Native|云原生布道师
bash - How do you break an array in groups of n - Stack Overflow

比較檔案是否一致
Fastest way to tell if two files are the same in Unix/Linux? - Stack Overflow