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Groups > comp.os.linux.advocacy > #471221
| From | owl <owl@rooftop.invalid> |
|---|---|
| Newsgroups | comp.os.linux.advocacy |
| Subject | Re: What is this BASH Code Doing? |
| Date | 2018-10-08 21:04 +0000 |
| Organization | O.W.L. |
| Message-ID | <az80b8034ga.h9o34@rooftop.invalid> (permalink) |
| References | <6dd66e7f-85b3-45a6-bfbd-0c039ddd6a0d@googlegroups.com> |
fr314159@gmail.com wrote:
> I want to install Foxit Reader on my Linux system but I will NEVER
> allow the commercial installer to run on my machine.
>
> An answer may be the ArchLinux bash script that is found here:
>
> https://pastebin.com/kjGhqpxu
>
> But I am not sure what this bash code is doing:
>
> _file="FoxitReader.enu.setup.${pkgver}(${_foxitrevision}).x64.run"
> LANG=C grep --only-matching --byte-offset --binary \
> --text $'7z\xBC\xAF\x27\x1C' "${_file}" | cut -f1 -d: |
> while read _position
> do
> dd if="${_file}" \
> bs=1M iflag=skip_bytes status=none skip=${_position} \
> of="${pkgname}-installer/bin-${_position}.7z"
> done
>
The 7z\xBC\xAF\x27\x1C is just the 7z file magic. It looks like
it's looking it's looking for that magic, and stripping any bytes
that might precede it. When I create a 7z file, and run the grep
part of this code, without the cut pipe, it always results in:
0:7z��'
If I put four bytes before the magic, it gives:
4:7z��'
So, dd is just jumping to the start of the 7z magic before it
writes.
I don't know why why the magic would be in a different
place than the start of the file (maybe for obfuscation?).
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What is this BASH Code Doing? fr314159@gmail.com - 2018-10-08 11:02 -0700
Re: What is this BASH Code Doing? Steve Carroll <frelwizzen@gmail.com> - 2018-10-08 11:27 -0700
Re: What is this BASH Code Doing? owl <owl@rooftop.invalid> - 2018-10-08 21:04 +0000
Re: What is this BASH Code Doing? "F. Russell" <fr@random.info> - 2018-10-08 22:09 +0000
Re: What is this BASH Code Doing? Steve Carroll <frelwizzen@gmail.com> - 2018-10-08 15:52 -0700
Re: What is this BASH Code Doing? Steve Carroll <frelwizzen@gmail.com> - 2018-10-09 08:17 -0700
Re: What is this BASH Code Doing? Steve Carroll <frelwizzen@gmail.com> - 2018-10-09 14:14 -0700
Re: What is this BASH Code Doing? Steve Carroll <frelwizzen@gmail.com> - 2018-10-09 02:04 -0700
Re: What is this BASH Code Doing? Steve Carroll <frelwizzen@gmail.com> - 2018-10-09 11:25 -0700
Re: What is this BASH Code Doing? "F. Russell" <fr@random.info> - 2018-10-10 09:11 +0000
Re: What is this BASH Code Doing? Steve Carroll <frelwizzen@gmail.com> - 2018-10-10 02:30 -0700
Re: What is this BASH Code Doing? Melzzzzz <Melzzzzz@zzzzz.com> - 2018-10-10 18:29 +0000
Re: What is this BASH Code Doing? fr314159@gmail.com - 2018-10-10 11:42 -0700
Re: What is this BASH Code Doing? Steve Carroll <fretwizzer@gmail.com> - 2018-10-10 13:32 -0700
Re: What is this BASH Code Doing? "F. Russell" <fr@random.info> - 2018-10-10 22:59 +0000
Re: What is this BASH Code Doing? Silicon Vee <siliconvee1945@yahoo.com> - 2018-10-11 01:03 +0200
Re: What is this BASH Code Doing? Steve Carroll <frelwizzen@gmail.com> - 2018-10-10 16:32 -0700
Re: What is this BASH Code Doing? Steve Carroll <frelwizzen@gmail.com> - 2018-10-10 16:16 -0700
Re: What is this BASH Code Doing? DFS <nospam@nospam.com> - 2018-10-10 20:01 -0400
Re: What is this BASH Code Doing? Silicon Vee <siliconvee1945@yahoo.com> - 2018-10-11 02:02 +0200
Re: What is this BASH Code Doing? DFS <nospam@nospam.com> - 2018-10-10 20:11 -0400
Re: What is this BASH Code Doing? Steve Carroll <frelwizzen@gmail.com> - 2018-10-10 17:18 -0700
Re: What is this BASH Code Doing? "F. Russell" <fr@random.info> - 2018-10-11 00:22 +0000
Re: What is this BASH Code Doing? Silicon Vee <siliconvee1945@yahoo.com> - 2018-10-11 02:28 +0200
Re: What is this BASH Code Doing? Steve Carroll <frelwizzen@gmail.com> - 2018-10-10 17:34 -0700
Re: What is this BASH Code Doing? Steve Carroll <fretwizzer@gmail.com> - 2018-10-10 17:45 -0700
Re: What is this BASH Code Doing? Steve Carroll <frelwizzen@gmail.com> - 2018-10-10 17:50 -0700
Re: What is this BASH Code Doing? "F. Russell" <fr@random.info> - 2018-10-11 00:58 +0000
Re: What is this BASH Code Doing? Steve Carroll <fretwizzer@gmail.com> - 2018-10-10 18:15 -0700
Re: What is this BASH Code Doing? Silicon Vee <siliconvee1945@yahoo.com> - 2018-10-11 04:28 +0200
Re: What is this BASH Code Doing? Steve Carroll <frelwizzen@gmail.com> - 2018-10-10 14:59 -0700
Re: What is this BASH Code Doing? Steve Carroll <frelwizzen@gmail.com> - 2018-10-08 17:26 -0700
Re: What is this BASH Code Doing? Steve Carroll <frelwizzen@gmail.com> - 2018-10-09 09:04 -0700
Re: What is this BASH Code Doing? Steve Carroll <frelwizzen@gmail.com> - 2018-10-09 15:33 -0700
Re: What is this BASH Code Doing? Steve Carroll <frelwizzen@gmail.com> - 2018-10-10 03:32 -0700
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