Difference between revisions of "Batch"

Revision as of 21:21, 15 December 2010

Batch files are the original ms-dos scripting language. A batch file is a script that contains a list of ms-dos commands, with one command per line. When you try to execute the batch file, it will execute the ms-dos commands, one after another, waiting for each command to finish before starting the next one.

Examples

For

The following example will output each line of the text file to the stdout:

> FOR /F %i in (list.txt) DO @echo %~ni

The following example will allow to parse and edit the environment variables:

> for /F %i in ('dir /B /S *_1.dat') do @set fil=%i & copy /Y !fil! !fil:1=2!

If you want to write FOR loops in a batch file instead of the command line, then use %%i instead of %i.

To place the first line of a file into a variable:

> SET /P _MyVar=<MyFilename.txt

To place the last line of a file into a variable:

> FOR /F "tokens=*" %A IN (C:\boot.ini) DO SET TestVar=%A

Nested FOR Loops

> FOR /F %a IN (filelist.txt) DO (FOR /F %b IN (salinitytemperature.txt) DO echo %a %b)

Nested FOR loops encapsulated in a batch file

for /F %%a in (%1) do (
    for /R %%b in (../*) do (
        echo %%a
        echo %%b
    )
)

Delimeters

This command will look for the first underscore in the list of filenames and will split each filename in two at the underscore.

> for /f "tokens=1-4 delims=_" %i in ('dir /B *.eps') do @echo  %i %j %k %l

Check out this site for more.

Misc

Manipulating environment variables

Substring find and replace

> set HELLO=HelloWorld
> echo %HELLO:l=w%
echo> HewwoWorwd

Extension stripping

> For /F %%i in (list.txt) DO echo %%~ni

See more help

>set /?

Escaping characters

<,|,> and % characters are special characters in dos. To escape them use the ^ character or a double %

> echo ^<example^>
<example>

Displaying blank lines

Use command echo to display a blank line instead of its default status result

>echo.

Sample applications

Copy a clean MOHID project

Here's a combination with a batch file, that creates a clean copy of a MOHID simulation:

> copysimulation MySimulation

#copysimulation.bat content
#Input argument %1 stands for simulation name
@echo off
set COPYHOME=C:\Program Files\2gif
xcopy %1\*.* %1_copy /E /EXCLUDE:%COPYHOME%\exclui.txt
perl %COPYHOME%/replace.pl 's/%2/\.\.\/\.\./g' *
perl %COPYHOME%/replace.pl 's/\\/\//g' *
@echo on

Remove all openmp directives from the code

NOTE: cygwin or gnuwin32 with all the gnu tools executables must be installed and accessible from the path command line.

$ for /F %i in ('dir /B /S *.F90') do @cat %i | grep -v !$OMP > %~ni.tpp
$ for /F %i in ('dir /B /S *.tpp') do @copy %i %~ni.F90
$ for /F %i in ('dir /B /S *.tpp') do @del %i

Appending hourly data files from Instituto Hidrográfico

$ for /F %i in ('dir /B *') DO @cat %i | grep MCAS >> one-file.txt

External References

• Batch files tutorial;
• for command reference;
• windows nt command-line reference;
• gnuwin32 download