Eu sempre amo expandir o bash para isso:
ls
name-with-stuff-i-dont-want-to-type
mv name-with-stuff-i-dont-want-to-type{,_old}
ls
name-with-stuff-i-dont-want-to-type_old
Isso é equivalente a:
mv name-with-stuff-i-dont-want-to-type name-with-stuff-i-dont-want-to-type_old
Para prefixar:
ls
name-with-stuff-i-dont-want-to-type
mv {,new_}name-with-stuff-i-dont-want-to-type
ls
new_name-with-stuff-i-dont-want-to-type
Para facilitar a renomeação de arquivos:
ls
fileFOOname
mv file{FOO,BAR}name
ls
fileBARname