This is Windows 10. The question is very simple, I simply don't know the proper syntax to do this.
This will list all files ending in .log:
dir /s /p *.log
This will truncate a file:
echo|set /p=>"myfile.log"
What I would like to do is pipe the output of the first operation to the second operation, thus truncating the matching files returned by dir. How would I do this?
Piping for the normal cmd isn't that common in Windows. So for the cmd you'd probably have to get a list of those files in variable and use a for loop to process them. Maybe you could also directly use the dir command in the loop.
I'd opt for PowerShell, which does a similar thing but is way more readable in my opinion:
Get-ChildItem -Recurse -Filter "*.log" | Clear-Content
If you want to confirm every single file (the /P on your dir does pause every screen) you could use the -Confirm switch on Clear-Content.
If you'd want to use a for loop for whatever reason and use echo you could use:
Get-ChildItem -Recurse -Filter "*.log" | %{ echo $null > $_; }
To just collect the dir output in the log file, drop the /p and redirect dir /s *.log >myfile.log
That will create a new file, deleting any previous contents.
If you want the full path on each line, instead of listing by subdirectory, use /b dir /s /b *.log >myfile.log
dir returns to 0 bytes - not write anything to myfile.log. There is no myfile.log - that is just an example. Edited my post to clarify this.
Commented
Nov 22, 2016 at 13:59
dir /s /p *.log?Use the following batch file (test.cmd):
@echo off
setlocal
for /f "tokens=*" %%f in ('dir /b /s *.log') do (
echo|set /p=>"%%f"
)
endlocal
Example usage:
> dir /s /p *.log
Volume in drive F is Expansion
Volume Serial Number is 3656-BB63
Directory of F:\test
02/10/2016 17:02 2,305 test.log
1 File(s) 2,305 bytes
Directory of F:\test\test
02/10/2016 17:02 2,305 test.log
1 File(s) 2,305 bytes
Directory of F:\test\test with space
02/10/2016 17:02 2,305 test.log
1 File(s) 2,305 bytes
Total Files Listed:
3 File(s) 6,915 bytes
0 Dir(s) 1,737,619,595,264 bytes free
> test
> dir /s /p *.log
Volume in drive F is Expansion
Volume Serial Number is 3656-BB63
Directory of F:\test
24/11/2016 10:39 0 test.log
1 File(s) 0 bytes
Directory of F:\test\test
24/11/2016 10:39 0 test.log
1 File(s) 0 bytes
Directory of F:\test\test with space
24/11/2016 10:39 0 test.log
1 File(s) 0 bytes
Total Files Listed:
3 File(s) 0 bytes
0 Dir(s) 1,737,619,607,552 bytes free
