GNU bug report logs - #77252
cat lost content when used in cmd.exe

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Message #5 received at submit <at> debbugs.gnu.org (full text, mbox):

From: "anmikf" <anmikf <at> qq.com>
To: "bug-coreutils" <bug-coreutils <at> gnu.org>
Subject: cat lost content when used in cmd.exe
Date: Tue, 25 Mar 2025 15:55:53 +0800

[Message part 1 (text/plain, inline)]

English is not my native language; please excuse typing errors.please read attachment "catbug"

[Message part 2 (text/html, inline)]

[catbug (application/octet-stream, attachment)]

Message #8 received at 77252 <at> debbugs.gnu.org (full text, mbox):

From: Pádraig Brady <P <at> draigBrady.com>
To: anmikf <anmikf <at> qq.com>, 77252 <at> debbugs.gnu.org
Subject: Re: bug#77252: cat lost content when used in cmd.exe
Date: Tue, 25 Mar 2025 17:18:09 +0000

On 25/03/2025 07:55, anmikf via GNU coreutils Bug Reports wrote:
> English is not my native language; please excuse typing errors.please read attachment "catbug"

That's too large a file to send to a mailing list really.
In essence the data is this I think:

  { yes 111122223333444455556666777788889999 | head -n51366; echo ABC: }

I don't understand your problem.
Are you saying everything is output except the letter 'B' from the above?
What --version of cat is this?

You may find an online LLM useful
for generating the bug report.

thank you,
Pádraig.

Message #11 received at 77252 <at> debbugs.gnu.org (full text, mbox):

From: Pádraig Brady <P <at> draigBrady.com>
To: anmikf <anmikf <at> qq.com>, 77252 <at> debbugs.gnu.org
Subject: Re: 回复： bug#77252: cat lost content when used in cmd.exe
Date: Wed, 26 Mar 2025 13:00:05 +0000

tag 77252 notabug
close 77252
stop

On 26/03/2025 07:43, anmikf wrote:
> 在Git for windows的Git Bash里面执行`cat catbug`,文件内容能完全显示。
> 但是在Win10的cmd.exe里面执行`"C:\Program Files\Git\usr\bin\cat.exe" catbug`,文件内容不能完全显示，会丢失第51367行的字符'B'，经过测试发现会丢失第1900544个字节。
> ------------------------
> Execute `cat catbug` in Git Bash for Windows, and the file content will be fully displayed.
> However, when executing `"C:\Program Files\Git\usr\bin\cat.exe" catbug` in cmd. exe of Win10, the file content cannot be fully displayed and the character 'B' on line 51367 will be lost. After testing, it was found that the 1900544th byte will be lost.

I think you're using version 8.32 of cat (according to https://packages.msys2.org/packages/coreutils)
You're having an issue on a 64KiB boundary, i.e. the first byte in a 64KiB buffer is not displayed.
I strongly suspect cmd.exe is at issue here not cat, as a bug like that in cat would not go unnoticed.
Also given it works under git bash for windows, that also absolves cat.exe from coreutils.

thanks,
Pádraig

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