There was a paperback edition availble from Amazon.com three years ago.

Presently, Worldcat shows copies available in two Tennessee libraries.

Diary of a Confederate Soldier Paperback – 8 Aug 2013
by Samuel Tate Blair (Author)

This is the complete wartime diary of Confederate Soldier Samuel Tate Blair, chronicling his service as a gunnery sergeant from November 1861 to May 1865. Blair fought in some of the war’s fiercest and most signficant battles, including Shiloh, Vicksburg, Chickamauga and Atlanta. He was severely wounded in May 1864 at Cartersville, Georgia and spent the remainder of the war in hospital. After the war, Blair studied medicine and practiced in Tennessee and Missouri. His grandson, James T. Blair, Jr., was the 44th governor of Missouri, serving from 1957-1961. The diary is interspersed with letters home and alongside a chronology of the war's main events. As such it comprises an invaluable first-hand account of the horrors and mundanity of war.
http://www.amazon.co.uk/Diary-Confederate-Soldier-Samuel-Blair/dp/1492114022

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Diary of Samuel Tate Blair, Confederate soldier.
https://www.worldcat.org/title/diary-of-samuel-tate-blair-confederate-soldier/oclc/41331487&referer=brief_results