Dos - For Statement

> Procedural Languages > Dos (Win32 Shell Scripting) and Utilities

1 - About

The for statement:

To get more information on this statement, just type in a command dos:

help for
Advertising

3 - Variable

3.1 - Mode

The variable element initialization differs from one interaction mode to the other

  • %variable is used in on-line mode
  • %%variable is used in (batch|script) mode

3.2 - Syntax Enhancement

To understand the syntax enhancement, you must understand the FOR loop constructs. This why they are at the end of this page: see variable enhancement

4 - Type For

4.1 - File Set

4.1.1 - Syntax

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

where:

  • the /R option indicates if you want to recursively walk the directory tree from the path parameter (default: current directory)
  • % and %% indicates that we are in presence of a variable
    • % is used in on-line mode
    • %% is used in batch mode
  • variable is a single letter variable
  • set is a file set data definition (not the set function of variable). You can use the ster wildcard and use a set definiton. To get all doc and txt files, you will define (set) as:
(*.doc *.txt )
  • command-parameters: specifies parameters or switches for the specified command.
Advertising

4.1.2 - Example

4.1.2.1 - List all files in one directory
:: In the command line
for %v in (*.bat) do echo %v
:: In a DOS Script
for %%v in (*.bat) do echo %%v

where:

  • v is the variable
  • *.bat is the set of all file with a bat extions file

Example of output:

start.bat
Hello.bat
4.1.2.2 - List all files in the directory tree

Current directory = C:\Users\gerard

:: In the command line
for /R %v in (*.bat) do echo %v
:: In a DOS Script
for /R %%v in (*.bat) do echo %%v
:: Is the same that
for /R C:\Users\gerard %%v in (*.bat) do echo %%v
C:\Users\gerard\AppData\Local\Temp\cleanup_bootstrap.bat
C:\Users\gerard\AppData\Local\Temp\env.bat
C:\Users\gerard\AppData\Local\Temp\startup.bat
C:\Users\gerard\AppData\Local\Temp\update_acls1.bat
C:\Users\gerard\AppData\Local\Temp\update_acls2.bat
..........

4.2 - Directory Set

4.2.1 - Syntax

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

where:

  • % and indicates that we are in presence of a variable * % is used in on-line mode * is used in batch mode
  • variable is a single letter variable
  • set is a directory set data definition (not the set function of variable). You can use the star wildcard and use a set definition. To get all directory which start with Doc and , you will define (set) as:
(App* Pic*)
  • command-parameters: specifies parameters or switches for the specified command.
Advertising

4.2.2 - Example

:: In the command line
FOR /D %v IN (App* Pic*) DO echo %v
:: In a DOS Script
FOR /D %%v IN (App* Pic*) DO echo %%v

where:

  • v is the variable
  • (App* Pic*) is the set of directory that start with App and Pic

Example of output from the User Home:

AppData
Pictures

4.3 - Sequence of number

4.3.1 - Syntax

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

where:

  • /L indicate a number for loop
  • start indicates the first number of the sequence
  • end indicates the last number of the sequence
  • step indicate the number of number to jump

4.3.2 - Example

The set is a sequence of numbers from start to end, by step amount.

FOR /L %v IN (3,3,15) DO echo %v

Output:

3
6
9
12
15

4.4 - (File|Text|Command Output) Parsing

for parsing with the /F switch, see DOS - Parsing (File, Command, Variable) - FOR F option

5 - Variable Enhancement

5.1 - Syntax

%~mI

where:

  • %~
  • m is a modifier (They are not case sensitive)
  • I is valid FOR variable

Picking upper case variable names like %I makes it more readable and avoids confusion with the modifiers, which are not case sensitive.

5.2 - List of modifiers

List of syntax enhancement with example: In the below examples %I can be replaced by other valid values.

5.2.1 - No Modifiers: removing any surrounding quotes

%~I expands %I removing any surrounding quotes (“)

5.2.2 - f: fully qualified path name

%~fI expands %I to a fully qualified path name

for %I in (.) do @echo %~fI
c:\Users\gerard

5.2.3 - d: Drive letter only

%~dI expands %I to a drive letter only

for %I in (.) do @echo %~dI
c:

5.2.4 - p: Path only

%~pI - expands %I to a path only

for %I in (.) do @echo %~pI
\Users\

5.2.5 - n: file name only

%~nI expands %I to a file name only

for %I in (.) do @echo %~nI
gerard

5.2.6 - x: file extension only

%~xI expands %I to a file extension only

for %I in (temp.xml) do @echo %~xI
.xml

5.2.7 - s: short names only

%~sI expanded path contains short names only. Example from C:\Program Files

for %I in (.) do @echo %~sI
C:\PROGRA~1

5.2.8 - a: file attributes of file

%~aI expands %I to file attributes of file

for %I in (.) do @echo %~aI
d--------

5.2.9 - t: date/time of file

%~tI expands %I to date/time of file

for %I in (.) do @echo %~tI
2013-10-08 12:01

5.2.10 - z: size of file

%~zI expands %I to size of file

for %I in (.) do @echo %~tI
28672

5.2.11 - $PATH: Search file in directories

%~$PATH:I searches the directories listed in the PATH environment variable and expands %I to the fully qualified name of the first one found. If the environment variable name is not defined or the file is not found by the search, then this modifier expands to the empty string. Example: Where can I find SQLPLUS.exe

for %I in (sqlplus.exe) do @echo %~$PATH:I
C:\app\gerard\product\12.1.0\dbhome_1\BIN\sqlplus.exe

PATH can be replaced by other valid values.

5.2.12 - Modifiers Combination

The modifiers can be combined to get compound results:

  • %~dpI - expands %I to a drive letter and path only
  • %~nxI - expands %I to a file name and extension only
  • %~fsI - expands %I to a full path name with short names only
  • %~dp$PATH:I - searches the directories listed in the PATH environment variable for %I and expands to the drive letter and path of the first one found.
  • %~ftzaI - expands %I to a DIR like output line

6 - Support

6.1 - %% was unexpected at this time

See variable

lang/dos/for.txt · Last modified: 2019/05/21 09:58 by gerardnico