Usage: /usr/bin/iscsi-pr [OPTION...] <iscsi-url>
  -i, --initiator-name=iqn-name  Initiator name to use
  -d, --debug                    Enable debug
  -?, --help                     Show this help message
  -K, --param-rk=RK              PR Out: parameter reservation key (RK is in hex)
  -S, --param-sark=SARK          PR Out: parameter service action reservation key (SARK is in hex)
  -T, --prout-type=TYPE          PR Out: type field
  -G, --register                 PR Out: Register
  -R, --reserve                  PR Out: Reserve, SARK only(register sark implicitly)
  -L, --release                  PR Out: Release, SARK only. This program releases TYPE 7 and TYPE 8 only
  -C, --clear                    PR Out: Clear, SARK only
  -P, --preempt                  PR Out: Preempt, use SARK to preempt reservation from RK
  -X, --preempt-remove           PR Out: Preempt, use SARK to preempt reservation from RK, then release SARK and remove SARK
  -k, --read-keys                PR In:  Read Keys (default)
  -r, --read-reservation         PR In:  Read Reservation
  -c, --report-capabilities      PR In:  Report Capabilities
  -s, --read-full-status         PR In:  Read Full Status

iSCSI URL format : "iscsi://[<username>[%<password>]@]<host>[:<port>]/<target-iqn>/<lun>"
<host> is either of:
  "hostname"       iscsi.example
  "ipv4-address"   10.1.1.27
  "ipv6-address"   [fce0::1]

PR Out TYPE field value meanings:
  0:    obsolete (was 'read shared' in SPC)
  1:    write exclusive
  2:    obsolete (was 'read exclusive')
  3:    exclusive access
  4:    obsolete (was 'shared access')
  5:    write exclusive, registrants only
  6:    exclusive access, registrants only
  7:    write exclusive, all registrants
  8:    exclusive access, all registrants