%%a是什么意思?
我理解上下文但不知道如何使用它。
例如:
FOR %%a in (%HELP%) DO echo I don't Know what it means
%%a是什么意思?
我理解上下文但不知道如何使用它。
例如:
FOR %%a in (%HELP%) DO echo I don't Know what it means
%%a
指代你的 for 循环将要写入的变量名。
引用自 for /?
:
FOR %variable IN (set) DO command [command-parameters]
%variable Specifies a single letter replaceable parameter.
(set) Specifies a set of one or more files. Wildcards may be used.
command Specifies the command to carry out for each file.
command-parameters
Specifies parameters or switches for the specified command.
To use the FOR command in a batch program, specify %%variable instead
of %variable. Variable names are case sensitive, so %i is different
from %I.
for %%a in (A B C D E) do Echo %%a
产生
A
B
C
D
E
for %%a in (A B C) do (for %%b in (1 2 3) do Echo %%a:%%b)
生成
A:1
A:2
A:3
B:1
B:2
B:3
C:1
C:2
C:3