use warnings;
-my $path = '/sys/class/power_supply/BAT0/uevent';
+if (scalar @ARGV != 1 and (scalar @ARGV != 2 or not $ARGV[0] =~ /-[st]/)) {
+ print STDERR "Usage: $0 [-s | -t] <path/to/device>\n";
+ print STDERR "\n";
+ print STDERR "Normally this is /sys/class/power_supply/BAT*.\n";
+ exit 1;
+}
+if (scalar @ARGV == 1) {
+ @ARGV = ('', $ARGV[0]);
+}
+
+my $path = "$ARGV[1]/uevent";
# No battery available.
-if (! -e $path) {
+if (not -e $path) {
+ print STDERR "'$path' not found.\n";
exit 1;
}
-my $screen_mode = (defined $ARGV[0] and $ARGV[0] eq '-s');
-my $tmux_mode = (defined $ARGV[0] and $ARGV[0] eq '-t');
+my $screen_mode = ($ARGV[0] eq '-s');
+my $tmux_mode = ($ARGV[0] eq '-t');
my %battery;