- Overview
- Part 1 – Getting Started
- Part 2 – Variables
- Part 3 – Return Codes
- Part 4 – stdin, stdout, stderr
- Part 5 – If/Then Conditionals
- Part 6 – Loops
- Part 7 – Functions
- Part 8 – Parsing Input
- Part 9 – Logging
- Part 10 – Advanced Tricks
Looping through items in a collection is a frequent task for scripts. It could be looping through files in a directory, or reading a text file one line at a time.
Old School with GOTO
The old-school way of looping on early versions of DOS was to use labels and GOTO statements. This isn’t used much anymore, though it’s useful for looping through command line arguments.
:args
SET arg=%~1
ECHO %arg%
SHIFT
GOTO :args
New School with FOR
The modern way to loop through files or text uses the FOR command. In my opinion, FOR is the single most powerful command in DOS, and one of
the least used.
GOTCHA: The FOR command uses a special variable syntax of % followed by a single letter, like %I. This syntax is slightly different when
FOR is used in a batch file, as it needs an extra percent symbol, or %%I. This is a very common source of errors when writing scripts. Should
your for loop exit with invalid syntax, be sure to check that you have the %% style variables.
Looping Through Files
FOR %I IN (%USERPROFILE%\*) DO @ECHO %I
Looping Through Directories
FOR /D %I IN (%USERPROFILE%\*) DO @ECHO %I
Recursively loop through files in all subfolders of the %TEMP% folder
FOR /R "%TEMP%" %I IN (*) DO @ECHO %I
Recursively loop through all subfolders in the %TEMP% folder
FOR /R "%TEMP%" /D %I IN (*) DO @ECHO %I