如何確定低級文件類型？

file(1)，當針對某些文件時，例如說“Debian 二進制包（格式 2.0）”*.deb或“OpenDocument 文本” *.odt。相反，我想有一種方法來確定使用哪種低級存檔類型：例如，對於 Debian 包可能是ar，對於 OpenDocument 文件可能是 ZIP。

我怎樣才能確定這一點？

將7z 16.02或更高版本與lp7zip 中的 (list) 選項一起使用

以下是一些範例輸出：

異端：

7z l test.odt 

(..)
Scanning the drive for archives:
1 file, 20969 bytes (21 KiB)

Listing archive: test.odt

--
Path = test.odt
Type = zip
Physical Size = 20969
(..)

債務：

7z l test.deb 

(..)
Scanning the drive for archives:
1 file, 47320946 bytes (46 MiB)

Listing archive: test.deb

--
Path = test.deb
Type = Ar
Physical Size = 47320946
SubType = deb
----
Path = data.tar.xz
Size = 47310792
Modified = 2017-03-09 00:04:52
Mode = -rw-r--r--
--
Path = data.tar.xz
Type = xz
Physical Size = 47310792
Method = LZMA2:26 CRC32
Streams = 1
Blocks = 1
(..)

轉：

7z l test.rpm 

(..)
Scanning the drive for archives:
1 file, 80356 bytes (79 KiB)

Listing archive: test.rpm

--
Path = test.rpm
Type = Rpm
Physical Size = 80356
Headers Size = 7726
CPU = x86_64
Host OS = linux
Created = 2016-06-06 11:01:01
----
Path = test.cpio.gz
Size = 72630
Created = 2016-06-06 11:01:01
--
Path = test.cpio.gz
Type = gzip
Headers Size = 10
(..)

tgz:

7z l test.tgz

Scanning the drive for archives:
1 file, 25617349 bytes (25 MiB)

Listing archive: test.tgz

--
Path = test.tgz
Type = gzip
Headers Size = 10
(..)

非檔案：

(..)
ERROR: test.sh : Can not open the file as archive

引用自：https://unix.stackexchange.com/questions/350894