Btw the song has other titles (Que la tortilla se vuelva / La hierba de los caminos) and is of Spanish origin so "tortilla" is Spanish omelette.
From there...
"The grass of the roads" is a theme that compiles verses that the republicans sang in the trenches during the civil war, from the first verse, which was appropriated by Corruco de Algeciras, singer of La Línea de la Concepción that made Manuel Vallejo himself cry the first time he heard him sing, up to the very popular "Let the rich eat bread and the rich eat shit." -Google translation.