Use CDPLAY environment variable to not type argument each time

Submitted by: hvd@terry.ping.dk

usr.sbin/cdplay/cdplay.1

@@ -6,13 +6,17 @@
 .Nd Audio CD player
 .Sh SYNOPSIS
 .Nm cdplay
-.Ar device
+.Op Ar device
 .Sh DESCRIPTION
 .Nm cdplay
 is a program to control an audio CD player. The device is a name such
 as cd0 or mcd0. 
 .Pp
- Currently supported commands are as follows:
+If the device not specified, the environment variable 
+.Ev CDPLAY
+will be used to find the cd device.
+.Pp
+Currently supported commands are as follows:
 .Bl -tag -width Cm
 .It Cm play first_track last_track
 Play from track 

usr.sbin/cdplay/cdplay.c

@@ -6,6 +6,7 @@
 #include <sys/file.h>
 #include <sys/cdio.h>
 #include <sys/ioctl.h>
+#include <stdlib.h>
 
 #define command(s) strncmp(cmd,s,strlen(s))==0
 
@@ -27,11 +28,16 @@ main (int argc, char **argv)
 {
     int rc;
 
-    if (argc != 2) {
-	fprintf(stderr, "Usage: cdplay <cd>\n<cd> is device name such as cd0 or mcd0\n");
-	exit(1);
-    }
-    cdname = argv[1];
+    switch (argc) {
+      case 2:  cdname = argv[1]; 
+          break;
+      case 1:  if(cdname = getenv("CDPLAY"))
+	  /* Break if CDPLAY is set */
+          break;
+      default: fprintf(stderr, "Usage: cdplay <cd>\n<cd> is device name such as cd0 or mcd0\n");
+	  exit(1);
+  };
+
     standalone = isatty (0);
     while (input ()) {
 	rc = 0;