rfh3273@galileo.rtn.ca.boeing.com (Dick Harrigill) (05/04/91)
I have a generic problem with writing batch files.
Can anyone provide a simple solution?
PROBLEM:
To be able to pass a path/directory to a batch file as a parameter,
and be able to act upon a file within that directory.
FOR EXAMPLE:
1. doit c:
2. doit a:\mydir
3. doit c:\mydir\
where file doit.bat references a file using %1 as the path.
Within doit.bat:
%1FILENAME will work with example 1 & 3 but not 2.
%1\FILENAME will work with example 2 but not 1 (as it will
incorrectly point to the root) and not 3
(as you will get a double \).
How do you write a generic batch file that will work with all cases above?
--
Dick Harrigill, an independent voice from: Boeing Commercial Airplanes
M/S 9R-49 PO BOX 3707 Renton Avionics/Flight Systems
Seattle, WA 91824 Computing Support
(206) 393-9539 rfh3273@galileo.rtn.ca.boeing.comts@uwasa.fi (Timo Salmi) (05/04/91)
In article <375@galileo.rtn.ca.boeing.com> rfh3273@galileo.rtn.ca.boeing.com (Dick Harrigill) writes: >PROBLEM: > To be able to pass a path/directory to a batch file as a parameter, > and be able to act upon a file within that directory. : Test for the existence of the file in each of the relevant directories and set an enrivroment variable to reflect which path is true. Then branch with a goto depending on the result of the test. There are probably neater solutions, but this is one.
fisher@sc2a.unige.ch (05/06/91)
In article <375@galileo.rtn.ca.boeing.com>, rfh3273@galileo.rtn.ca.boeing.com (Dick Harrigill) writes: > I have a generic problem with writing batch files. > Can anyone provide a simple solution? > > PROBLEM: > To be able to pass a path/directory to a batch file as a parameter, > and be able to act upon a file within that directory. > > FOR EXAMPLE: > 1. doit c: > 2. doit a:\mydir > 3. doit c:\mydir\ 4. doit . 5. doit .. SOLUTION: Use a little known trick to check the existence of a directory and a bit of fall-through logic. THE TRICK: In DOS the file NUL "exists" in every directory on any drive (even those beyond the LastDrive parameter or not yet SUBST'ed drives). How many installation batch files have you seen that ask you to create the target directory before running it? BATCH FILE: (Public Domain :-) @echo off rem Find out if %1 is a valid directory, store the result in '_vd' rem using the "directory\NUL" test. rem (Markus G. Fischer, Geneva CH, 1991) if no%1_arg == no_arg goto no_arg set _vd= if exist %1NUL if exist %1\NUL set _vd=%1 if no%_vd% == no if exist %1\NUL set _vd=%1\ if no%_vd% == no if exist %1.\NUL set _vd=%1 if no%_vd% == no goto no_vd echo %0: working on "%_vd%filename.ext" set _vd= goto end :no_arg echo usage: %0 directory echo checks if "directory" exists goto end :no_vd echo %0 error: directory %1 not found! :end echo. BUGS: There must be enough environment space to store the variable. Hope this helps! Markus G. Fischer, Dept of Anthropology, Geneva CH
userAKDU@mts.ucs.UAlberta.CA (Al Dunbar) (05/09/91)
In article <1991May5.210006.417@sc2a.unige.ch>, fisher@sc2a.unige.ch writes: >In article <375@galileo.rtn.ca.boeing.com>, rfh3273@galileo.rtn.ca.boeing.com >(Dick Harrigill) writes: >> I have a generic problem with writing batch files. <<<deletions: wants "if exist directoryname" capability>>> > > SOLUTION: > Use a little known trick to check the existence of a directory and > a bit of fall-through logic. > <<< deletions: explanation that NUL exists in all directories>>> <<< code fragment follows: >>> > > set _vd= > if exist %1NUL if exist %1\NUL set _vd=%1 > if no%_vd% == no if exist %1\NUL set _vd=%1\ > if no%_vd% == no if exist %1.\NUL set _vd=%1 > if no%_vd% == no goto no_vd A neat trick, but not foolproof. It handles even the oddball "..".."..".."..", but catches you when you try to back up past the root directory. Where it does fail is with a directory name such as ".."""""", which it heralds as an existing directory, even though CD and DIR object. You could go a step further and check for a file such as direxist in the tentative directory. If it exists, the directory must exist; if not, create it and try again. If it then exists the directory must exist; if not the directory either doesn't exist or the disk is full. Oh, well, .BAT files aren't quite DCL! -------------------+------------------------------------------- Al Dunbar | Edmonton, Alberta | Disclaimer: "I disclaim disclaimers" CANADA | -------------------+-------------------------------------------
userAKDU@mts.ucs.UAlberta.CA (Al Dunbar) (05/10/91)
In article <RN.1208@mts.ucs.UAlberta.CA>, I wrote: >In article <1991May5.210006.417@sc2a.unige.ch>, fisher@sc2a.unige.ch writes: >>In article <375@galileo.rtn.ca.boeing.com>, rfh3273@galileo.rtn.ca.boeing.com >>(Dick Harrigill) writes: >>> I have a generic problem with writing batch files. > ><<<deletions: wants "if exist directoryname" capability>>> > >> >> SOLUTION: >> Use a little known trick to check the existence of a directory and >> a bit of fall-through logic. >> > ><<< deletions: explanation that NUL exists in all directories>>> ><<< code fragment follows: >>> >> >> set _vd= >> if exist %1NUL if exist %1\NUL set _vd=%1 >> if no%_vd% == no if exist %1\NUL set _vd=%1\ >> if no%_vd% == no if exist %1.\NUL set _vd=%1 >> if no%_vd% == no goto no_vd > >A neat trick, but not foolproof. It handles even the <<<deleted explanation that ".."""""" appears to be valid>>> Here is another way it fails: If you pass the name "BILLY" where no such directory exists, but a file called BILLY.NUL does exist, the above code would declare "BILLY" as a valid directory. The solution to this glitch is to look for NUL.XXX (which has the same properties of existence as NUL), because BILLY.NUL.XXX can't exist to throw the code off the track. Note also, that other device names (CON, PRN) seem to work in place of NUL, but using NUL makes more sense. -------------------+------------------------------------------- Al Dunbar | Edmonton, Alberta | Disclaimer: "I disclaim disclaimers" CANADA | -------------------+-------------------------------------------