asm_space.sh

#!/bin/sh
$ORACLE_HOME/bin/sqlplus -s / as sysasm <<EOF
 
SELECT NAME, STATE, ROUND(TOTAL_MB/1024, 2) TOTAL_GB,
       ROUND((TOTAL_MB - FREE_MB)/1024, 2) USED_GB,
       ROUND(FREE_MB/1024, 2) FREE_GB
FROM V\$ASM_DISKGROUP;
 
exit;
EOF

Output:

NAME                           STATE         TOTAL_GB    USED_GB    FREE_GB
------------------------------ ----------- ---------- ---------- ----------
DATADISK                       MOUNTED            800     348.14     451.86