I'm sure many of us have needed to run libcurl3 and libcurl4 on Ubuntu 18 for some reason at any point in time.
On Ubuntu 18.04 (Bionic) libcurl3 and libcurl4 cannot coexist. Many third party packages, libraries, etc require libcurl3 while curl itself requires libcurl4.
Please note, this solution is only for precompiled commands (and potentially binaries, not tested). This was tested on a C# binary.
First you'll need to get a copy of libcurl3 and save it to your
/usr/lib directory. You can do that by running:
$ sudo apt-get install libcurl3 -y $ cp /usr/lib/x86_64-linux-gnu/libcurl.so.3 /usr/lib/
Then remove libcurl3 and reinstall libcurl4:
$ sudo apt-get install libcurl4 libcurl4-openssl-dev -y
env LD_PRELOAD=/usr/lib/libcurl.so.3 to any commands that require libcurl3.