This would be a more secure and much more ergonomic option:

    pwgen --ambiguous --no-capitalize --secure 12

Your command produces passwords like this:

    X3_>r"9'

I can't even copy it by double clicking on it.

Mine produces passwords like this:

    stq7nt4nvh3g

It even has more entropy by one or two orders of magnitude.

I usually end up piping the result to a file so I can see it and edit if I need to and cat | pbcopy the file contents to the clipboard and save it in 1password. After that, 1password either fills in the password for me or copying it is just a button click.

The main issue I face is that some web sites will either not allow passwords longer than a certain length or will only allow some special characters.

TIL!