🚀 go-pugleaf

mlevis@ringer.cs.utsa.edu (Mike Levis) writes:

>In article <1992Aug19.045036.5132@uwasa.fi> ts@uwasa.fi (Timo Salmi) writes:
>>In article <1992Aug18.233207.1159@cs.ubc.ca> yogi@cs.ubc.ca (Yossi Gil) writes:
>>
>>if not exist %1 goto _out
>>if exist echo.* erase echo.*
>>copy %1 echo.* > nul
>>for %%f in (echo.*) do %%f > ext
>>type ext
>>if exist ext erase ext
>>:_out

>I modified this.  The following batch file will work somewhat.
>It is not efficient (it copies the file that you want
>to find the extension of), and it does not do much
>error checking (it fails if the filename has no extension),
>but it works if the filename either has an extension or
>the filename is not given.

>It creates a variable xyz to have the filename extension.
>It creates (and later deletes) a temporary batch file
>called tmp.bat .  Essentially, tmp.bat is a clone of the
>original batch file below, but it also has the filename
>extension as part as the batch file code.

>@echo off
>set xyz=
>if %1.==. goto end_batch
>del echo.*
>copy %1 echo.* > nul
>for %%f in (echo.*) do %%f > tmp.dat
>if exist %0 copy %0+tmp.dat tmp.bat > nul
>if not exist %0 copy %0.bat+tmp.dat tmp.bat > nul
>call tmp.bat
>del tmp.bat
>:end_batch
>if %xyz%.==. set xyz=^Z

>Important!!!  The ^Z means Control-Z (End of file).  It
>must be on the same line as the last command, not on the
>line following it.  Since ^Z is on the same line as the
>last command, we can append the filename extension to
>a copy of the batch file and run the copy to set the
>variable.

>Even though this code works somewhat, I'm sure there is a
>much better way of doing it.

Perhaps a more elegant variation to the above is (I didn't bother
with all the chekcs)

copy %1 echo.*
for %f in (echo.*) do %%f >> %0
set ext=^Z

This batch file will auto destruct but it is not too difficult to
remedy this: copy %0 to some tmp and rexecute it. The trick in the
above is that DOS rereads the batch file after each command.  If you
don't believe it, try the following automodifying batch file:

	echo echo >> %0.bat






>>..................................................................
>>Prof. Timo Salmi
>>Moderating at garbo.uwasa.fi anonymous FTP archives 128.214.87.1
>>Faculty of Accounting & Industrial Management; University of Vaasa
>>Internet: ts@uwasa.fi Bitnet: salmi@finfun   ; SF-65101, Finland


>-- 
>==== Mike Levis   mlevis@ringer.cs.utsa.edu ====
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Joseph (Yossi) Gil                 {alberta,uw-beaver,uunet}!ubc-cs!yogi
Dept. of Computer Science          yogi@cs.ubc.ca (cs.ubc.ca=137.82.8.5)
6356 Agricultural Road., Univ. of B.C.,             Tel: +1-604-822-8175
Vancouver, British Columbia, V6T 1Z2, Canada.       Fax: +1-604-822-5485