Batch file read in var and write back

Question

I need to count every time a computer is turn off or restarted. Thus I believe i can do this with a batch file by adding it to the start menu. Thus everytime you turn on PC it will run. When it runs it should

open c:\count.txt
read in the value on that text file
add 1 to it
write the value to the text file
exit.

but I have not used batch files much and could not figure out how to read in the number from the text file.

Alternatively, you may store such data in registry with `REG` or `SETX`. — LS_ᴅᴇᴠ, Sep 17 '13 at 07:54
i need to have least impact on the pc, messing with reg is risky or so i think. — Glen Morse, Sep 17 '13 at 07:58
Ok. By myself, I would prefer it to write to drive root path. — LS_ᴅᴇᴠ, Sep 17 '13 at 08:08

Stephan · Accepted Answer · 2018-10-19T13:39:49.700

4

based on your idea (updating a counter in a file):

rem open c:\count.txt
rem read in the value on that text file
set /p count=<c:\count.txt
rem add 1 to it
set /a count+=1
rem write the value to the text file
>c:\count.txt echo.%count%
rem exit.
exit

Notice: Take care, that you choose a path the user has write access to. (C:\ may not work without privileges)

edited Oct 19 '18 at 13:39

answered Sep 17 '13 at 12:10

Stephan

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Good example of "set /p" and "set /a". – zentrunix Sep 17 '13 at 12:29
i like this , its quick and easy for me to understand :D One question i have though is how will this work if 1. the count.txt file got deleted? would it create the file again. would it give an error cause its a blank file? would it still add 1.. I could test these out i guess. just restarting a computer , or restarting this computer is something i dont want to do due to the applications running on it. but will if you can not answer these. Thanks Glen – Glen Morse Sep 18 '13 at 03:18
if count.txt does not exist, `set /p` will give an error. Nevertheless, `set /a` will correctly "add" one. @foxidrive: thanks for the edit :) – Stephan Sep 18 '13 at 12:59

score 1 · Answer 2 · answered Sep 17 '13 at 05:08

1

This is a solution from MS-DOS days. The c:\count.txt filesize isn't going to be an issue for any realistic number.

To reset the counter delete c:\count.txt

@echo off
>>c:\count.txt echo 1
echo Count is up to:
find /c "1" <c:\count.txt

answered Sep 17 '13 at 05:08

foxidrive

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I dont understand this, this will readin the count.txt and echo out first line right? not sure what >>c:\count line does or the find. – Glen Morse Sep 17 '13 at 08:00
Try it a few times - and examine the file. That should make it clearer. – foxidrive Sep 17 '13 at 09:18
LOL not elegant, but functional! @GlenMorse: every run of the batch will add a line `1` to the file. The `find` counts the `1`s (`/c`) – Stephan Sep 17 '13 at 11:50

Batch file read in var and write back

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