GOOGLE-AUTHENTICATOR(1) GOOGLE-AUTHENTICATOR(1) (NAME) google-authenticator - TOTP (SYNOPSIS) google-authenticator [] google-authenticator(1) . (DESCRIPTION) google-authenticator(1) . ~/.google_authenticator . libqrencode QR Google Authenticator . google-authenticator(1) . - Google Authenticator . . . google-authenticator(1) . . google-authenticator(1) TOTP ( ) HOTP ( ) . (OPTIONS) : . -c, --counter-based . -t, --time-based . . (HOTP) : -w, --window-size=W . . . . . -W, --minimal-window . (TOTP) : -D, --allow-reuse, -d, --disallow-reuse () . (man-in-the-middle) . -w, --window-size=W . . . . ( ) ( ) . . . -W, --minimal-window . -S, --step-size=S S . . . . -s, --secret=FILE . -f, --force . -l, --label=LABEL otpauth://. -i, --issuer=ISSUER otpauth://. -Q, --qr-mode=none|ansi|utf8 QR. QR (none) QR ANSI (ansi) (utf8). QR . . -r, --rate-limit=N, -R, --rate-time=M, -u, --no-rate-limit N M . (brute-force) : N M . . . -e, --emergency-codes=N N . . -q, --quiet . -h, --help . (SEE ALSO) Google Authenticator : Google two-factor authentication user manual GOOGLE-AUTHENTICATOR(1)