pwgen: generate password by remap(sha512(username:secret@hostname)).
-u : username
-h : hostname
add <username string> <-d bool> <-u string>
save a account to the filesystem("~/.pwgen").
-d : this account will be the default
del <username string> <-u string>
delete a account from the filesystem.
ls
list all saved accounts.
gen <hostname string> <username string> <-l int> <-p bool> <-u string> <-h string> <-s bool> <-d bool>
generate a password. if 'username' is empty, use the default account. this is the default sub-command.
-l : length of the password, in range (1-64)
-p : do not send to the clipboard, only print.
-s : auto save this account.
-d : auto save this account as the default.