for (对一组文件中的每一个文件执行某个特定命令)

Windows 2000, XP, and later syntax

FOR %variable IN (set) DO command [command-parameters]

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.

If Command Extensions are enabled, the following additional forms of the FOR command are supported:

FOR /D %variable IN (set) DO command [command-parameters]

If set contains wildcards, then specifies to match against directory names instead of file names.

FOR /R [[drive:]path] %variable IN (set) DO command [command-parameters]

Walks the directory tree rooted at [drive:]path, executing the FOR statement in each directory of the tree. If no directory specification is specified after /R, then the current directory is assumed. If set is only a single period (.) character, then it will enumerate the directory tree.

FOR /L %variable IN (start,step,end) DO command [command-parameters]

The set is a sequence of numbers from start to end, by step amount. So (1,1,5) would generate the sequence 1 2 3 4 5 and (5,-1,1) would generate the sequence (5 4 3 2 1).

FOR /F ["options"] %variable IN (file-set) DO command [command-parameters]
FOR /F ["options"] %variable IN ("string") DO command [command-parameters]
FOR /F ["options"] %variable IN ('command') DO command [command-parameters]

or, if usebackq option present:

FOR /F ["options"] %variable IN (file-set) DO command [command-parameters]
FOR /F ["options"] %variable IN ('string') DO command [command-parameters]
FOR /F ["options"] %variable IN (`command`) DO command [command-parameters]

The parameter fileset is one or more file names that are the source of input. Each file in filenameset is opened, read, and processed before going on to the next one. Processing consists of reading in the file, breaking it up into individual lines of text, and then parsing each line into zero or more tokens. The body of the for loop is then called with the variable value(s) set to the found token string(s). By default, /F passes the first blank separated token from each line of each file. Blank lines are skipped. You can override the default parsing behavior by specifying the optional "options" parameter. A quoted string contains one or more keywords to specify different parsing options. The keywords are:

Some examples might help:

FOR /F "eol=; tokens=2,3* delims=, " %i in (myfile.txt) do @echo %i %j %k

parses myfile.txt, ignoring lines beginning with a semicolon, passing the 2nd and 3rd token from each line to the for body, with tokens delimited by commas and spaces. Notice the for body statements reference %i to get the 2nd token, %j to get the 3rd token, and %k to get all remaining tokens after the 3rd. For file names that contain spaces, you need to quote the file names with double quotes. To use double quotes in this manner, you need to use the usebackq option. Otherwise, the double quotes are interpreted as defining a literal string to parse.

%i is explicitly declared in the for statement, and the %j and %k are implicitly declared via the tokens= option. You can specify up to 26 tokens via the tokens= line, provided it does not cause an attempt to declare a variable higher than the letter 'z' or 'Z'. Remember, FOR variable names are case-sensitive, global, and you can't have more than 52 total active at any one time.

You can also use the FOR /F parsing logic on an arbitrary string. To do so, specify fileset as a single-quoted string enclosed in parentheses. It will be parsed as a single line of input from a file.

Finally, you can use the FOR /F command to parse the output of a command. You do this by making the fileset between the parenthesis a back quoted string. It's treated as a command line, which passes to a child CMD.EXE and its output is captured into memory and parsed as a file. So the following example:

FOR /F "usebackq delims==" %i IN (`set`) DO @echo %i

would enumerate the environment variable names in the current environment.

The substitution of the FOR variable references were enhanced, and you can now use the following optional syntax:

The modifiers can be combined to get compound results:

In the examples above, %I and PATH can be replaced by other valid values. The %~ syntax is terminated by a valid FOR variable name. Picking uppercase variable names like %I makes it more readable and avoids confusion with the modifiers, which are not case-sensitive.

Windows 95, 98, ME syntax

FOR %variable IN (set) DO command [command-parameters]

To use the FOR command in a batch program, specify %% variable instead of % variable.

for /F %%A in ("pics.txt") do If %%~zA equ 0 del pics.txt

In the above example, if the file pics.txt was found in the current directory and was equal to 0 in file size, that file would be deleted.

for /f "tokens=1-5 delims=/ " %%d in ("%date%") do rename "hope.txt" %%e-%%f-%%g.txt

The example above takes the date from %date% and uses its data to rename the hope.txt file to the current date.

for /f %F in ('dir /b /a-d ^| findstr /vile ".tiff .jpg"') do del "%F"

The for command above would delete everything in the current directory that did not end with a .tiff or .jpg.