Is there alternative to https://www.zynamics.com/bindiff.html that works for Linux x86_64 binaries, works on Linux, (and preferably does not require IDA Pro, however if needed it seems that IDA can run on Linux so it may be fine)?
VBinDiff at http://www.cjmweb.net/vbindiff/
Below is the same message as above. But with details if you're interested in those.
VBinDiff (Visual Binary Diff) code at https://github.com/madsen/vbindiff
VBinDiff displays files in hexadecimal and ASCII (or EBCDIC). It can also display two files at once, and highlight the differences between them.
VBinDiff is CLI only though (Command Line Interface)