Remember the challenge?
Write a batch file that will read and save its own window title.
After the first results were tested, additional conditions were formulated:
Administrator:
prefix added in UAC enabled Windows versionsSeven "contestants" sent me eight scripts.
Carlos M.'s batch file does not really qualify for the challenge, as it generates VBScript and an executable to complete the task (which it does flawlessly).
The scripts presented here are the latest versions.
Some were written before the first publication of the intermediate results, some after.
To me the challenge is not a contest, but more like a brainstorm session.
I think everybody learned from it.
Five tests were performed on each batch file, each test on Windows 7 Ultimate SP1 (64-bit) as well as Windows XP Professional SP3 (32-bit):
START "Passed the first test" CMD /K GetTitle.bat
FOR /L %%A IN (1,1,5) DO START "Failed" CMD /K
START "Passed" CMD /K GetTitle.bat
FOR /L %%A IN (1,1,5) DO START "Failed" CMD /K
FOR /L %%A IN (10,1,20) DO START "Test %%A" CMD /K GetTitle.bat
Administrator:
prefix.Administrator:
prefix.Administrator:
from the title may not be enough (besides, it might be part of the intended title).START
command, trimmed from the result?
Author (click for source code) |
Test 1: does it work at all? |
Test 2: multiple console windows |
Test 3: multiple simultaneous instances |
Test 4: strip prefix only in Win7 |
Test 5: strip appended command line |
|||||
---|---|---|---|---|---|---|---|---|---|---|
XP | Win7 | XP | Win7 | XP | Win7 | XP (1) | Win7 | XP | Win7 | |
Batch Files | ||||||||||
Antonie v.d. Baan | Passed | Passed | Passed | Passed | Failed | Failed | Passed | Passed | No | No |
Brian Williams | Passed | Passed | Passed | Passed | Passed | Passed | Passed | Passed | Yes | Yes |
Jean François Larvoire | Passed | Failed | Passed | N/A | Failed | N/A | Passed | N/A | No | N/A |
Jiri Hofreiter (with WMIC) | Passed | Passed | Passed | Passed | Failed | Failed | Passed | Passed | No | No |
Jiri Hofreiter (without WMIC) | Passed | Passed | Passed | Passed | Failed | Failed | Passed | Passed | No | No |
Justin Goldspring | Passed | Failed | Passed | N/A | Failed | N/A | Passed | N/A | Yes | N/A |
Menno Vogels | Passed | Passed | Passed | Passed | Failed | Failed | Passed | Passed | No | No |
Author (click for source code) |
Test 1: does it work at all? |
Test 2: multiple console windows |
Test 3: multiple simultaneous instances |
Test 4: strip prefix only in Win7 |
Test 5: strip appended command line |
|||||
XP | Win7 | XP | Win7 | XP | Win7 | XP (1) | Win7 | XP | Win7 | |
Executables | ||||||||||
Carlos M. | Passed | Passed | Passed | Passed | Passed | Passed | Passed | Passed | Yes | Yes |
Rob van der Woude | Passed | Passed | Passed | Passed | Passed | Passed | Passed | Passed | Yes | Yes |
Notes: | 1 | In XP, nothing should be stripped from the title. Tested with the command START "Administrator: test" CMD /K GetTitle.bat By the way: in Windows 7 this command does not result in a double Administrator: prefix, TITLE Administrator: test does. |
2 | The failures of the batch files by Jean François Larvoire and Justin Goldspring in Windows 7 are caused by the Administrator: prefix.We're still working on it. |
|
3 | Jiri Hofreiter's GetTitle.bat without WMIC more or less did pass most tests, but in case the batch file is called by its name only (no path, nor extension) it may append the batch file's extension when restoring the title. We're still working on it. |
💾 Download all contestants' sources.
All "contestants" seem to agree on the use of TASKLIST to retrieve the window title.
Correctly running multiple instances of the batch files was the hardest requirement to meet.
The %Random%
variable starts with the same value in every newly opened console window.
This makes it almost impossible to create truly random temporary file names or temporary titles.
For that very reason I wrote GetTitle.exe in C# when I needed to reliably read the title.
However, Brian Williams' latest version proves that it is possible in batch.
A way to make random numbers more random is by using the fraction of seconds of the current time.
WMI's Win32_LocalTime
class looks promising, but unfortunately the MilliSeconds
property is not implemented in Windows.
The closest alternative is the fraction (hundredths) of seconds in the TIME
command's output (not TIME /T
as it won't even display the seconds):
FOR /F "tokens=1* delims=:" %%A IN ('VER ^| TIME') DO ( FOR /F "tokens=3,4 delims=:.," %%C IN ("%%~B") DO ( SET AlmostTrueRandom=%Random%%%C%%D ) )
The code above appends the seconds (%%C
) and hundredths of seconds (%%D
) to a not so random %Random%
number.
%Random%
can even be left out, as Brian Williams' solution proves.
However, on my fast Windows 7 test system, sometimes 4 console windows were started within a 10 microseconds interval, so the starting time was not a reliable source for a unique number.
Brian solved that problem not by making a better random generator, but by waiting approximately one second (PING
), checking for duplicate temporary titles, and changing them to the then current time if a duplicate was found.
The process is repeated until there are no more duplicates left.
Brilliant in its simplicity.
I would like to thank all "contestants" for sharing their ideas, research and time.
And whenever we find better solutions, the published source code will be updated.
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