Runs a specified command for each file in a set of files.
You can use the for command within a batch program or directly from the command prompt.
To use for in a batch program, use the following syntax:
for %%variable in (set) do command [command-parameters]
To use for from the command prompt, use the following syntax:
for %variable in (set) do command [command-parameters]
%%variable or %variable
Represents a replaceable variable. The for command replaces %%variable (or %variable) with each text string in the specified set until the command (specified in the command parameters) processes all the files. Use %%variable to carry out the for command within a batch program. Use %variable to carry out for from the command prompt.
Specifies one or more files or text strings that you want to process with the specified command. The parentheses are required.
Specifies the command that you want to carry out on each file included in the specified set.
Specifies any parameters or switches that you want to use with the specified command (if the specified command uses any parameters or switches).
In and do are not parameters, but they are required in the for command. If you omit either of these keywords, Windows NT displays an error message.
To avoid confusion with the batch parameters %0 through %9, you can use any character for variable except the numerals 0 through 9. For simple batch programs, a single character such as %%f may be all that is necessary.
You can use multiple values for variable in complex batch programs to distinguish different replaceable variables.
The set parameter can represent a single group of files or several groups of files. You can use wildcards (* and ?) to specify a file set. The following are valid file sets:
(*.doc) (*.doc *.txt *.me) (jan*.doc jan*.rpt feb*.doc feb*.rpt) (ar??1991.* ap??1991.*)
When you use the for command, the first value in set replaces %%variable (or %variable) and Windows NT carries out the specified command in order to process this value; this continues until Windows NT has processed all the files (or groups of files) that correspond to the value (or values) in set.
Suppose you want to use the type command to display the contents of all the files in the current directory that have the extension .DOC or .TXT. To do this and to use the replaceable variable %f, type the following command at the command prompt:
for %f in (*.doc *.txt) do type %f
In this example, each file that has the .DOC or .TXT extension in the current directory is substituted for the %f variable until the contents of every file are displayed. To use this command in a batch file, you simply replace every occurrence of %f with %%f. Otherwise, Windows NT ignores the variable and displays an error message.
Windows NT supports command switches, pipes, and redirection that you may want to use with the specified command. For example, to redirect the output of the previous example to PRN (the default printer port), you would type the following command:
for %f in (*.doc *.txt) do type %f > prn: