while(my $line=<DATA>){ $_ .= $line  }

s/(u)\W?(s)\W?\s*\W?\s*(army)/uc($1.$2).'-'.ucfirst$3/gieo;

print

# STDOUT:
#
# US-Army
# the US-Army has been
# US-Army
# USA Army . US-Army

__DATA__

U.S. Army
the US army has been
US - Army
USA Army . U-S- Army
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