Bash IF:多个条件 [英] Bash IF : multiple conditions

查看：911 发布时间：2020/5/17 1:18:19 bash if-statement nested conditional-statements multiple-conditions

本文介绍了Bash IF:多个条件的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！

我一直在尝试使此功能工作几个小时，但我无法使其正常工作:

I've been trying to make this thing work for a couple of hours but I can't get it to work :

if [ "$P" = "SFTP" -a "$PORT" != "22" ] || [ "$P" = "FTPS" && [ "$PORT" != "990" -a "$PORT" != "21" ] ] ; then

有人可以帮助我吗?我知道可以这样写多个条件:

Can someone help me ? I know that multiple conditions can be written like this :

if [ "$P" = "SFTP" ] && [ "$PORT" != "22" ]; then

但是如何像我的第一个示例中那样概括这些条件?

but how can I imbricate theses conditions like in my first example?

您不能将表达式嵌套在单括号中.应该这样写:

You can't nest expressions in single brackets. It should be written like this:

if [ "$P" = "SFTP" -a "$PORT" != "22" ] || [ "$P" = "FTPS" -a "$PORT" != "990" -a "$PORT" != "21" ] ; then

这可以写为单个表达式，如下:

This can be written as a single expressions as:

if [ \( "$P" = "SFTP" -a "$PORT" != "22" \) -o \( "$P" = "FTPS" -a "$PORT" != "990" -a "$PORT" != "21" \) ] ; then

尽管不是与所有shell完全兼容.

although is is not fully compatible with all shells.

由于您正在使用bash，因此可以使用双括号使命令更具可读性:

Since you are using bash, you can use double brackets to make the command more readable:

if [[ ( $P = "SFTP" && $PORT != "22" ) || ( $P = "FTPS" && $PORT != "990" && $PORT != "21" ) ]] ; then

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