When using qtum-cli official guides, unofficial guides, examples posted in various locations, and the syntax "qtum-cli help" returns can get you into deep trouble with a pass phrase at this time. Shell variables are not escaped when using double quotes, no quotes, or even single quotes in the case a character is a single quote itself.
qtum-cli encryptwallet "qtum_is*$$" will set the $$ portion of the passhrase to the PID BASH is running on, if using BASH. Actually, this is quite a mess I've made with this combination :
[r[email protected] ~]$ echo "qtum_is*$$"
This ticket was closed, but I believe another set of eyes should confirm
This was a perplexing issue initially as I knew a pass phrase I had set worked and unlocked my wallet as expected. After a reboot, my pass phrase no longer worked, so I reverted to a backup, and still no luck. I dug around for information on HD wallets, and as best I can conclude most if not all HD wallets where initially implemented to use a mnemonic seed in lieu of a pass phrase which would never have special characters which explains the lack of a widespread problem with HD wallets, I believe this only effects QTUM.
Hopefully this finds its way to those that may have made the same accidental discovery.../wipes sweat
Be Well, and thanks to the QTUM team, this project is amazing!