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devel / comp.unix.shell / Re: Check the hashbang (magic number) in a executable file.

Re: Check the hashbang (magic number) in a executable file.

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https://www.novabbs.com/devel/article-flat.php?id=4399&group=comp.unix.shell#4399

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Subject: Re: Check the hashbang (magic number) in a executable file.
From: hongyi.z...@gmail.com (hongy...@gmail.com)
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by: hongy...@gmail.com - Mon, 20 Sep 2021 08:41 UTC

On Monday, September 20, 2021 at 12:13:27 AM UTC+8, Chris Elvidge wrote:
> On 19/09/2021 03:42 pm, Lew Pitcher wrote:
> > On Sat, 18 Sep 2021 17:00:56 -0700, hongy...@gmail.com wrote:
> >
> >> On Saturday, September 18, 2021 at 11:36:19 PM UTC+8, Lew Pitcher wrote:
> > [snip]
> >>> Hongy also seems to be assuming that a "non-script executable file" only
> >>> consists of an ELF executable. Under Linux, this is not true, as almost
> >>> /any/ file can be executed using the binfmt_misc facility. This facility
> >>> allows the sysop to define new "magic numbers" for "non-script executable"
> >>> files (such as a+x WAV files, or a+x pdf files) and the interpreter that
> >>> the kernel will automagically invoke to execute that sort of file.
> >>>
> >>> See /usr/src/linux/Documentation/binfmt_misc.txt for details,
> >>
> >> $ ls /usr/src/linux/Documentation/binfmt_misc.txt
> >> ls: cannot access '/usr/src/linux/Documentation/binfmt_misc.txt': No such file or directory
> >
> > Did you install the appropriate kernel source code?
> >
> > /usr/src/linux usually symlinks to the Linux kernel source code (which is
> > named with the full kernel version, something like /usr/src/linux-4.4.276)
> > and the Documentation subdirectory of that source code directory contains
> > the binfmt_misc.txt file.
> I found :
> /usr/src/linux-5.13.13/Documentation/admin-guide/binfmt-misc.rst

This file comes from linux-doc package:

$ apt-file search binfmt-misc.rst
linux-doc: /usr/share/doc/linux-doc/admin-guide/binfmt-misc.rst.gz
linux-doc: /usr/share/doc/linux-doc/html/_sources/admin-guide/binfmt-misc.rst.txt

> >
> > If you don't want to install the kernel source code, you might look at
> > https://lwn.net/Articles/679310/
> > which contains a version of the binfmt_misc.txt file
> >
> >>
> >>> or
> >>> https://linuxgazette.net/118/lg_tips.html#tips.2 for my short summary.
> >>
> >> Thank you for your wonderful and elaborate tips.
> >
> > You're welcome
> >
>
>
> --
> Chris Elvidge
> England

Subject	Author
Check the hashbang (magic number) in a executable file.	hongy...@gmail.com
Re: Check the hashbang (magic number) in a executable file.	Eli the Bearded
Re: Check the hashbang (magic number) in a executable file.	Keith Thompson
Re: Check the hashbang (magic number) in a executable file.	Lew Pitcher
Re: Check the hashbang (magic number) in a executable file.	Lew Pitcher
Re: Check the hashbang (magic number) in a executable file.	Ben Bacarisse
Re: Check the hashbang (magic number) in a executable file.	Lew Pitcher
Re: Check the hashbang (magic number) in a executable file.	Ben Bacarisse
Re: Check the hashbang (magic number) in a executable file.	Lew Pitcher
Re: Check the hashbang (magic number) in a executable file.	Ben Bacarisse
Re: Check the hashbang (magic number) in a executable file.	Lew Pitcher
Re: Check the hashbang (magic number) in a executable file.	Lew Pitcher
Re: Check the hashbang (magic number) in a executable file.	David W. Hodgins
Re: Check the hashbang (magic number) in a executable file.	Janis Papanagnou
Re: Check the hashbang (magic number) in a executable file.	hongy...@gmail.com
Re: Check the hashbang (magic number) in a executable file.	Lew Pitcher
Re: Check the hashbang (magic number) in a executable file.	hongy...@gmail.com
Re: Check the hashbang (magic number) in a executable file.	Lew Pitcher
Re: Check the hashbang (magic number) in a executable file.	Chris Elvidge
Re: Check the hashbang (magic number) in a executable file.	David W. Hodgins
Re: Check the hashbang (magic number) in a executable file.	hongy...@gmail.com
Re: Check the hashbang (magic number) in a executable file.	Spiros Bousbouras
Re: Check the hashbang (magic number) in a executable file.	Kenny McCormack
Re: Check the hashbang (magic number) in a executable file.	hongy...@gmail.com
Re: Check the hashbang (magic number) in a executable file.	David W. Hodgins
Re: Check the hashbang (magic number) in a executable file.	hongy...@gmail.com