bash 脚本中的 ${0%/*} 是什么意思？
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What is the meaning of ${0%/*} in a bash script?
提问by user785099
I am trying to understand a test script, which includes the following segment:
我正在尝试理解一个测试脚本，其中包括以下部分：
SCRIPT_PATH=${0%/*}
if [ "$ var="foo/bar/baz"
$ echo "$var"
foo/bar/baz
$ echo "${var}"
foo/bar/baz
$ echo "${var%/*}"
foo/bar
" != "$SCRIPT_PATH" ] && [ "$SCRIPT_PATH" != "" ]; then
cd $SCRIPT_PATH
fi
What does the ${0%/*}stand for? Thanks
代表什么${0%/*}？谢谢
回答by c00kiemon5ter
It is called Parameter Expansion. Take a look at this pageand the rest of the site.
它被称为Parameter Expansion。看看这个页面和网站的其余部分。
What ${0%/*}does is, it expands the value contained within the argument 0(which is the path that called the script) after removing the string /*suffix from the end of it.
什么${0%/*}是，它在从它的末尾删除字符串后缀后扩展包含在参数 0（这是调用脚本的路径）中/*的值。
So, $0is the same as ${0}which is like any other argument, eg. $1which you can write as ${1}. As I said $0is special, as it's not a realargument, it's always there and represents name of script. Parameter Expansion works within the {}-- curly braces, and %is one type of Parameter Expansion.
所以，$0是一样的${0}是像任何其他说法，如。$1你可以写成${1}. 正如我所说$0，它很特别，因为它不是真正的参数，它始终存在并代表脚本名称。参数扩展在{}-- 花括号内工作，%是参数扩展的一种。
%/*matches the last occurrence of /and removes anything (*means anything) after that character. Take a look at this simple example:
%/*匹配最后一次出现/并删除*该字符之后的任何内容（意味着任何内容）。看看这个简单的例子：
