These are some diary entries written in 1916 by Captain Alexander Stewart while serving with the 3rd Scottish Rifles on the Somme, during WWI.  I read some excerpts in the March 2008 issue of Harpers.  A book is available for download, online, at http://www.grandfathersgreatwar.com/index.html

June 30
The finest thing that ever happened in the tranches was the rum ration, and never was it more needed than on the Somme.  Yet some blasted, ignorant fool of a general — damned in this world and the next — wanted to stop it and, for a time, did.  The man must be worse than the lowest type of criminal, have no knowledge of the conditions in which the troops exist, and be entirely out of touch with the men who are unfortunate enough to have him as their commander.  He should have been taken up to the line and frozen in the mud.  I would have then very willingly sat on his head, as he was a danger to the whole army.  Curse him.  Those who have not spent a night standing or sitting or lying in mud with an east wind blowing and the temperature below freezing may think that I am extravagant in my abuse of the man who denied the soldiers their rum rations.  Those who have will know that I am too temperate.

August 26
Leave High Wood for trenches north of Bazentinle-Grand.  The flies in this part of the line are a perfect plague.  They cover everything.  They make it very difficult for a man to eat, as they cover the food he is about to put in his mouth.

September 1
While on a march, I was unable to get on my horse and had to be pushed up by my men.  When up, I could not get down.  An awkward predicament when suffering from dysentery.

Just goes to show you the similarities between trench  warfare and sailing.  I have left out the most graphic entries.