During these years in the South, He was in overall military command of combined Red Armies in hundreds of skirmishes.

请教各位老师，这里的He was in overall military command 该如何理解，如果翻译成他是全军的总指挥，那么这里为什么要有个in，如果翻译成他在总体的指挥当中，好像偏离了句子的意思，希望老师指点。