Windows batch files

• Windows batch files

• Windows Batch Scripting tutorial

To write a batch file

1. Put commands in a file with a name like PROG.BAT
2. From command line:

    notepad prog.bat 

3. To run it type PROG

4. Does it have to be in the PATH?
   • Windows will run progs found in dirs in the environment variable %path%
   • And it will run progs found in the current dir.

Script to get started

@echo off
rem the above line prevents the script echoing back the commands
rem is a comment

dir

Some features

1. Pipes:

    dir | find "string" | sort
   

   Example:

   Go into henryiv_1
   find "Scot" act*.html
   find "Scot" act*.html | find "Scots"
   find "Scot" act*.html | find /v "Scots"
   
   

2. Redirection:

    dir > file
   

3. Environment variables:

   
   set myvar=string
   echo myvar is %myvar%  
   
     echo path is %path%
   
     copy %1 %homepath%\backup
   
   

Flow of control statements

1. IF and command-line arguments and string compare:

   
   if '%1'=='' echo no arg  
   
   if '%1'=='' ( echo no arg ) else ( echo arg )
   
   

2. FOR loops and CALL of another batch file:

     for %%i in (*.html) do call secondprog %%i
   

3. multiple statements in block:

   
   for %%i in (*.*) do (
     echo %%i
     dir %%i
   )
   
   

4. IF EXIST

   
   IF EXIST "C:\Program Files\Mozilla Firefox" (
     echo Firefox exists
   ) ELSE (
     echo Firefox missing
   )
   
   

   Cannot change this layout around too much.

5. We can get around the lack of directory wildcards with a FOR loop:

   @echo off
   for /d %%d in ("r*") do find "Ireland" %%d\*html
   

   This is the equivalent of:

   grep Ireland r*/*html  
   

Misc

1. exit /b
   exit the script
   (with no argument it will close the cmd window)

But there are more powerful Windows command-lines.