#!/usr/bin/perl -w
use strict;

my @required = qw(
    CMD
    /bin/sh
    rds
    SysExec
    /oasis/bin/sysmenu
    /oasis/bin/TS_TextSrvcs
);

# invoke ps -a using backticks, read result into a list
# for each line, split on whitespace, keep 3rd element
# return a list of element => undef pairs

my %procs = map { (split ' ')[3], undef } qx/ps -a/;

# %procs now has a key named after each process
# values are empty, mere existence of the keys suffices


# now for each required process,
# check if it has an entry in the hash of running procs

my @missing = grep !exists $procs{$_}, @required;

# print the resulting list of missing processes

print map "NF: $_\n", @missing;

##</code><code>##

#!/usr/bin/perl -w
use strict;

my %procs = map { (split ' ')[3], undef } qx/ps -a/;

print map "NF: $_\n", grep !exists $procs{$_}, qw(
    CMD
    /bin/sh
    rds
    SysExec
    /oasis/bin/sysmenu
    /oasis/bin/TS_TextSrvcs
);

##</code><code>##

my %procs = map { chomp; $_ => undef } qx/ps -a ho comm/;