A recent upgrade has rendered file just about usless as it is only able to
identify text in the most limited sense.

for example:
$ file /usr/bin/file
/etc/magic, 4: Warning: using regular magic file `/usr/share/misc/magic'
/usr/bin/file: data

or:
$ file /usr/share/doc/file/*
/etc/magic, 4: Warning: using regular magic file `/usr/share/misc/magic'
/usr/share/doc/file/changelog.Debian.gz: data
/usr/share/doc/file/changelog.gz:        data
/usr/share/doc/file/copyright:           ASCII text
/usr/share/doc/file/README.Debian:       ASCII text
/usr/share/doc/file/README.gz:           data

I was expecting something a little more detailed like this from another
machine:
$ file /usr/bin/file /usr/share/doc/file/*
/usr/bin/file:                           ELF 32-bit LSB executable, Intel
80386, version 1 (SYSV), dynamically linked, interpreter /lib/ld-linux.so.2,
for GNU/Linux 2.6.32, BuildID [sha1]=b71c29fa59ca57fa80408b99e5b82c2118bd358d,
stripped
/usr/share/doc/file/changelog.Debian.gz: gzip compressed data, max compression,
from Unix
/usr/share/doc/file/changelog.gz:        gzip compressed data, max compression,
from Unix
/usr/share/doc/file/copyright:           ASCII text
/usr/share/doc/file/README.Debian:       ASCII text
/usr/share/doc/file/README.gz:           gzip compressed data, max compression,
from Unix

tags 863488 moreinfo unreproducible
thanks

Ben Hildred wrote...

Works for me:

/usr/bin/file: ELF 32-bit LSB shared object, Intel 80386, version 1 (SYSV), dynamically linked, interpreter /lib/ld-linux.so.2, for GNU/Linux 2.6.32, BuildID[sha1]=2f833ab1ff58c9e0ae5801481a0dff1da286f30b, stripped

(see the release notes why it's not "executable" any longer)

Results in the expected output.

What is in /usr/share/misc/magic, and where did the file(s) come
from?

    Christoph

empty directory. There is also  /usr/share/file/magic.mgc which is a
symbolic link pointing to ../../lib/file/magic.mgc. If I create a symbolic
link from /usr/share/misc/magic.mgc to /usr/lib/file/magic.mgc it starts
working again.

Ben Hildred wrote...

The /usr/share/misc/magic.mgc is shipped by libmagic-mgc so someone or
something must have removed it later. Do you have traces of your upgrade
path, like old version, new version or additional messages? The files
/var/log/apt/term.log and /var/log/dpkg.log should provide some information.

FWIW, I test-upgraded a jessie-i386 chroot, everything worked as expected.

    Christoph

for reference: I have two drives, one of which is system and the other is
for user data, it is mounted in /share.
I moved /usr/share to /share/usr/share with the command "mkdir -p
/share/data/usr && cp -r /usr/share /share/data/usr/share && rm /usr/share
&& ln -s /share/usr /share/data/usr/share"
after reboot everything worked as it should, except for man and file:

$ man man
man: command exited with status 1: (cd /usr/share/man &&
/usr/lib/man-db/zsoelim) | (cd /usr/share/man && /usr/lib/man-db/manconv -f
UTF-8:ISO-8859-1 -t UTF-8//IGNORE) | (cd /usr/share/man && preconv -e
UTF-8) | (cd /usr/share/man && tbl) | (cd /usr/share/man && nroff -mandoc
-rLL=193n -rLT=193n -Tutf8)
$ echo $?
3

$ file /usr/bin/file
/etc/magic, 4: Warning: using regular magic file `/usr/share/misc/magic'
/usr/bin/file: data
$ echo $?
0

$ cat /etc/os-release
NAME="Ubuntu"
VERSION="20.04.2 LTS (Focal Fossa)"
ID=ubuntu
ID_LIKE=debian
PRETTY_NAME="Ubuntu 20.04.2 LTS"
VERSION_ID="20.04"
HOME_URL="https://www.ubuntu.com/"
SUPPORT_URL="https://help.ubuntu.com/"
BUG_REPORT_URL="https://bugs.launchpad.net/ubuntu/"
PRIVACY_POLICY_URL="
https://www.ubuntu.com/legal/terms-and-policies/privacy-policy"
VERSION_CODENAME=focal
UBUNTU_CODENAME=focal

Никита Кудрявцев wrote...

In other words, you split /usr/ - that scenario isn't supported as it
possibly breaks symbolic links since Debian policy requires them to be
relative within /usr:

| 10.5. Symbolic links
|
| In general, symbolic links within a top-level directory should be
| relative, (...). (A top-level directory is a sub-directory of the root
| directory /.) For example, a symbolic link from /usr/lib/foo to
| /usr/share/bar should be relative (../share/bar), (...).

So the link /usr/share/misc/magic.mgc is relative but since it points
outside /usr/share/, will likely point to nowhere on your system. FWIW,
the links are made relative during build so it was quite hard to provide
absolute links even if I wanted to.

So if you really want to continue on your a bit unusual file system
layout, you'd have to adjust the link on your own, and possibly every
time the package gets updated.

About man, I have no idea why that one fails, strace -f however should
give you an idea.

    Christoph