更新时间:2023-10-06 13:21:16
您需要使用参数扩展为变量(S)要覆盖:
You need to use parameter expansion for the variable(s) you want to override:
$ cat override.sh
#!/bin/bash
: ${var1:=foo} # var1 will take on the value "foo" if not overridden
var2=${var2:-foo} # same thing but more typing
echo "var1 is $var1 | var2 is $var2"
$ ./override.sh
var1 is foo | var2 is foo
$ var1=bar var2=baz ./override.sh
var1 is bar | var2 is baz