Usando rename
:
rename -n 's/[^0-9]*//' *.txt # removes the first sequence of non-digits
rename -n 's/[^0-9]*\./\./' *.txt # removes the first sequence of non-digits followed by a dot
% rename -n 's/[^0-9]*//' *.txt
rename(ABC2011DEFG.txt, 2011DEFG.txt)
rename(HIJ2012KLMN.txt, 2012KLMN.txt)
rename(OPQ2013RSTU.txt, 2013RSTU.txt)
% rename -n 's/[^0-9]*\./\./' *.txt
rename(ABC2011DEFG.txt, ABC2011.txt)
rename(HIJ2012KLMN.txt, HIJ2012.txt)
rename(OPQ2013RSTU.txt, OPQ2013.txt)
Se os arquivos forem renomeados como esperado, remova a opção -n
.