How to delete unwanted lines from text file through batch file?

Question

I have a text file with following contents with some unwanted lines which I want to remove from the text file.

1233,pqry,01/11/2011
2365698,abcd,2011/01/12
,defghj,11/12/2013
,,,
,,,
,,,

In above example we can see there are multiple lines with comma separated. I want to remove those lines from my text file through batch file. Kindly help me out

Answer 1

ren myFile.txt myFile.txt.old
findstr /v /b /c:",,," myFile.txt.old > myFile.txt

Rename file as .old. Find all the lines not containing ",,," at the begin of line in old file and save it to original file.

EDITED - to adapt to comments

If lines to be removed are those with only commas (i will include spaces) and no other value, then this should work

for %%t in (c:\path\*.txt) do (
    ren "%%~ft" "%%~nxt.old"
    findstr /v /r /c:"^[, ]*$" "%%~ft.old" > "%%~ft"
)

For each file in path, rename the file to *.old, from this .old file extract any lines not containing (/v) the regular expression (/r) defined by the pattern (/c) : "from the start of line (^), followed by any sequence of spaces and commas ([, ]*) until reach the end of line ($)". The extracted lines are send to the original filename.