OpenStack - Quotas CLI Commands

Listing defaults quota
# nova quota-defaults (Note: while updating use defaults)

Updating default quota values 
Syntax: nova quota-class-update --instances <value> default (Note: while updating use default)
Syntax: nova quota-class-update --cpu <value> default (Note: while updating use default)
Syntax: nova quota-class-update --ram <value> default (Note: while updating use default)
instances, ram and cpu (different parameters can be combined)
# nova quota-class-update --instances 10 default

Listing quota for a particular tenants
Syntax: nova quota-show --tenant <tenant_ID>
# nova quota-show --tenant 9a54bc04965f40cd96e217d813b864ee

Updating quota for a particular tenants
Syntax: nova quota-update --instances <instance_value> <tenant_ID>
# nova quota-update --instances 15 3d69bce1f1b646edacb6e44e157d37b9

Viewing quota for a particular user against tenant
Syntax: nova quota-show --user <user_ID> --tenant <tenant_ID>
# nova quota-show --user 5e17d605cc10417ca8fab86d07307d5c --tenant 3d69bce1f1b646edacb6e44e157d37b9