=head1 NAME

aa-service - Helper for execline script to get service name/instance

=head1 SYNOPSIS

B<aa-service> [B<-D>] [B<-O> I<FILE|FD>] [B<-l>] I<PROG...>

=head1 OPTIONS

=over

=item B<-D, --double-output>

Enable double-output mode. Instead of using stdout for regular output, and
stderr for warnings and errors, everything is sent both to stdout and stderr.
This is intended to redirect stderr to a log file, so full output can be both
shown on console and logged.

B<Deprecation warning:> Note that this option has been deprecated and will be
removed in the next version; You should use B<--log-file> instead.

=item B<-h, --help>

Show help screen and exit.

=item B<-l, --log>

To use for a service logger run script, i.e. when current folder will be
subfolder I<log> of the servicedir.

=item B<-O, --log-file> I<FILE|FD>

Will duplicate all output (everything written to stdout or stderr) to the given
file or file descriptor. I<FILE|FD> can either be a (previously opened for
writing) file descriptor (must be > 2), or a file which will then be opened in
append mode.

=item B<-V, --version>

Show version information and exit.

=back

=head1 DESCRIPTION

This is a little helper for execline scripts (e.g. a service's I<run> script)
that will perform variable substitution on I<PROG...> for:

=over

=item B<SERVICE_NAME>

Will be the name of the current folder, i.e. full service name (e.g. I<foobar>
or I<bar@foo>)

=item B<SERVICE>

Will be the name of the service, without the instance name if any (e.g.
I<foobar> or I<bar>)

=item B<INSTANCE>

Will be the instance name of the service if any, else empty string (e.g. empty
string or I<foo>)

=back

This can be useful to get the service/instance name dynamicly; e.g. a service
could use I<${INSTANCE}> as argument, and a generic logger could then use
I</var/log/${SERVICE_NAME}> as logdir.

=head1 RETURN CODES

Return codes are somewhat unified inside B<anopa>. Odd return codes represent
fatal errors, and are detailled in B<anopa-rc>(1)

Possible even return codes for B<aa-service>(1) are:

=over

=item B<2>
Failed to perform variable substitution

=back