I just upgraded my former openSUSE_Leap_15.0 installation from build 139.1 to
147.1 which introduced an upgrade for pdsh. Although the manual page still
documents the "-a" flag to work for "all nodes from machines file", it throughs
an error when used.

# hostname
test-os15
# cat /etc/pdsh/machines
test-os15
# pdsh -a id
pdsh: invalid option -- 'a'
Usage: pdsh [-options] command ...
-S                return largest of remote command return values
-h                output usage menu and quit
-V                output version information and quit
-q                list the option settings and quit
-b                disable ^C status feature (batch mode)
-d                enable extra debug information from ^C status
-l user           execute remote commands as user
-t seconds        set connect timeout (default is 10 sec)
-u seconds        set command timeout (no default)
-f n              use fanout of n nodes
-w host,host,...  set target node list on command line
-x host,host,...  set node exclusion list on command line
-R name           set rcmd module to name
-M name,...       select one or more misc modules to initialize first
-N                disable hostname: labels on output lines
-L                list info on all loaded modules and exit
available rcmd modules: ssh,mrsh,exec (default: ssh)

This flag is a must-have for any large HPC cluster (for instance), because
having to spell all nodes in a long "-w host1,host2,host3,..." fashion is not
actually useful, so this is a clear regression from the former version which
would simply do the following for the above command:

# pdsh -a id
test-os15: uid=0(root) gid=0(root) groups=0(root)