Here's a classic traditional one below that no one's mentioned, from the singing of Sally Sloane called 'My Son Ted', also known as 'Mrs McGrath'.
Also, how about songs written by actual soldiers?
Does anyone know any 'post-able' ones? There was apparently a WW2 soldier's anti-war parody of Gracie Fields "Bless 'Em All" called "F*** 'em All"...
MY SON TED
"Oh, Mrs. McGrath," the sergeant said
"Would you like to make a soldier out of your son Ted
With a scarlett coat and a big red hat
Now, Mrs. McGrath, wouldn't you like that?"
With a too-ri-ra, fol-the-diddle-da,
So, Mrs. McGrath lived on the seashore
For a space of seven long years or more
Till she saw a big ship sailing into the bay
"Here's my son Teddy, wisha clear the way"
"Oh captain dear, wherever you be
Have you been sailing on the Mediterranean
Or have ye any tidings of my son Ted
Is the poor boy living or is he dead?"
Then up comes Ted without any legs
And in their place, he has two wooden pegs
She kissed him a dozen times or two
Saying "Holy Moses, is it you!"
"Oh then were ye drunk or were ye blind
That ye left your two fine legs behind
Or was it walking upon the sea
Wore your two fine legs from the knees?"
"No, I wasn't drunk and I wasn't blind
When I left my two fine legs behind
For a cannon ball on the fifth of May
Took my two fine legs from the knees away"
"Oh, then, Teddy my boy," the widow cried
"Your two fine legs were your mumma's pride
Them stumps of a tree wouldn't do at all
Why didn't you run from the big cannon ball?"
"All foreign wars I do proclaim
Between Don John and the King of Spain
And by heavens I'll make them rue the time
That they swept the legs from a child of mine."
Oh, then, if I had you back again,
I'd never let you go to fight the King of Spain,
For I'd rather have my Ted as he used to be
Than the King of France and his whole navy"