Problem with readline library in Ubuntu 18.04

Question

When trying to run sudo apt install debsig-verify which is needed to install Slack I got this error message:

You might want to run 'apt --fix-broken install' to correct these.   
The following packages have unmet dependencies:
libreadline-dev:i386 :
  Depends: libreadline7:i386 (= 7.0-3) but 7.0-0ubuntu2 is to be
installed
  Depends: libtinfo-dev:i386 but it is not going to be installed  libreadline7 : 
  Breaks: libreadline7:i386 (!= 7.0-3) but 7.0-0ubuntu2 is to be installed  \
libreadline7:i386 : 
  Breaks: libreadline7 (!= 7.0-0ubuntu2) but 7.0-3 is to be installed`

When I tried sudo apt --fix-broken install I got these results:

The following additional packages will be installed:
 libreadline7:i386
The following packages will be upgraded:
  libreadline7:i386
1 upgraded, 0 newly installed, 0 to remove and 25 not upgraded.
4 not fully installed or removed.
Need to get 0 B/128 kB of archives.
After this operation, 8 192 B of additional disk space will be used.
Do you want to continue? [Y/n] y
(Reading database ... 271028 files and directories currently installed.)
Preparing to unpack .../libreadline7_7.0-3_i386.deb ...
Unpacking libreadline7:i386 (7.0-3) over (7.0-0ubuntu2) ...
dpkg: error processing archive /var/cache/apt/archives>/libreadline7_7.0-3_i386.deb (--unpack):
 trying to overwrite shared '/usr/share/doc/libreadline7/changelog.Debian.gz', which is different from other instances of package libreadline7:i386
Errors were encountered while processing:
 /var/cache/apt/archives/libreadline7_7.0-3_i386.deb
E: Sub-process /usr/bin/dpkg returned an error code (1)`

Results of dpkg -S readline.h :

octave-doc: /usr/share/doc/octave/octave.html/Customizing-readline.html
nodejs: /usr/share/doc/nodejs/api/readline.html
libreadline-dev:amd64, libreadline-dev:i386: /usr/include/readline/readline.h

Results of dpkg -l | grep readline :

ii  libreadline-dev:amd64                             7.0-3                                                      amd64        GNU readline and history libraries, development files
iU  libreadline-dev:i386                              7.0-3                                                      i386         GNU readline and history libraries, development files
iF  libreadline7:amd64                                7.0-3                                                      amd64        GNU readline and history libraries, run-time libraries
iU  libreadline7:i386                                 7.0-0ubuntu2                                               i386         GNU readline and history libraries, run-time libraries
ii  readline-common                                   7.0-3                                                      all          GNU readline and history libraries, common files

Results of apt-cache policy libreadline7:i386 :

libreadline7:i386:
  Installed: 7.0-0ubuntu2
  Candidate: 7.0-3
  Version table:
     7.0-3 500
        500 http://ua.archive.ubuntu.com/ubuntu bionic/main i386 Packages
 *** 7.0-0ubuntu2 100
        100 /var/lib/dpkg/status

I've used 18.04 since I updated from the previous version. Maybe that's why something incompatible with 18.04 was added.

Results of sudo apt-get remove libreadline7 -a=i386 :

E: Command line option 'a' [from -a=:i386] is not understood in combination with the other options`

Results of sudo apt-get remove libreadline7 : https://pastebin.com/AUmqPyT2

Results of sudo apt-get remove readline7:i386 :

You might want to run 'apt --fix-broken install' to correct these.
The following packages have unmet dependencies:
libreadline-dev:i386 : 
  Depends: libreadline7:i386 (= 7.0-3) but it is not going to be installed
E: Unmet dependencies. Try 'apt --fix-broken install' with no packages (or specify a solution)

I also got another readline dependency error about. Should I post it here?

Solution

Remove libreadline7:i386 which is causing an unmet dependencies error. Uninstalling libreadline7:i386 will also solve the trying to overwrite error. Then install the Slack snap package which as a standalone package will not make any additional package management problems or require any additional dependency packages.

sudo apt --fix-broken install  
sudo apt remove libreadline-dev:i386 libreadline7:i386  

---

Slack is a native snap package in Ubuntu 18.10. To install Slack in all currently supported versions of Ubuntu open the terminal and type:

sudo snap install slack --classic  

This command will install the latest stable version of Slack which will also be updated automatically if an update is available.

To start Slack click on its icon in the Dash or run this command from the terminal:

snap run slack  

Slack has a free version for small teams or anyone who wants to try Slack for an unlimited period of time.

Comments

[BorisNepokrytyi]

Thanks. I try to follow tthat steps but after apt upgrade get: The following packages have unmet dependencies: libreadline-dev:i386 : Depends: libreadline7:i386 (= 7.0-3) but 7.0-0ubuntu2 is installed libreadline7 : Breaks: libreadline7:i386 (!= 7.0-3) but 7.0-0ubuntu2 is installed libreadline7:i386 : Breaks: libreadline7 (!= 7.0-0ubuntu2) but 7.0-3 is installed E: Unmet dependencies. Try 'apt --fix-broken install' with no packages (or specify a solution). Sorry for this wall of text.I have not understood formatting here yet

[BorisNepokrytyi]

i install it as apt install libreadline or using dpkg. I didn't compile it from source code

[guiverc]

You install PPA sourced files using apt install or dpkg. If installed as you said, it'll likely be found in your logs. Have you added PPA's to your sources? Can you add apt-cache policy libreadline7:i386 (please add additional info to your question/post; as it can be edited & has better formatting). You've added something not for 18.04 Bionic - as the error shows something needing an 'artful' (17.10) package (hence your error - packages.ubuntu.com/search?keywords=libreadline7)

[Alvin Liang]

And actually this has nothing to do with debsig-verify

[BorisNepokrytyi]

I updated post to respond your offer