# Test
command[check_disk_backup]=/usr/local/nagios-client/libexec/check_disk -w 20% -c 10% -p /nfs/backup

# Disk (partition and threshold via Args) check: Generic: dbAll
command[check_disk_args]=/usr/local/nagios-client/libexec/check_disk -w $ARG2$% -c $ARG3$% -p $ARG1$

which return:
[root@mgmt01 var]# /usr/local/nagios/libexec/check_nrpe -H 10.218.24.72 -c check_disk_backup        DISK WARNING - free space: /nfs/backup 63307 MB (12% inode=99%);| /nfs/backup=452980MB;413030;464659;0;516288
[root@mgmt01 var]# /usr/local/nagios/libexec/check_nrpe -H 10.218.24.72 -c check_disk_args -a /nfs/backup 20 10 -t 30
DISK CRITICAL - free space: /nfs/backup 63307 MB (12% inode=99%);| /nfs/backup=452980MB;516288;361401;0;516288