gpg-agent is a daemon to manage secret (private) keys independently from any protocol. It is used as a backend for gpg and gpgsm as well as for a couple of other utilities.
The agent is automatically started on demand by gpg, gpgsm, gpgconf, or gpg-connect-agent. Thus there is no reason to start it manually. In case you want to use the included Secure Shell Agent you may start the agent using:
If you want to manually terminate the currently-running agent, you can safely do so with:
gpgconf --kill gpg-agent
You should always add the following lines to your
whatever initialization file is used for all shell invocations:
GPG_TTY=$(tty) export GPG_TTY
It is important that this environment variable always reflects the
output of the
tty command. For W32 systems this option is not
Please make sure that a proper pinentry program has been installed under the default filename (which is system dependent) or use the option pinentry-program to specify the full name of that program. It is often useful to install a symbolic link from the actual used pinentry (e.g. /usr/local/bin/pinentry-gtk) to the expected one (e.g. /usr/local/bin/pinentry).
See Option Index, for an index to GPG-AGENT's commands and options.