$ for i in *; do mv "$i" "${i,,}"; done
April 20, 2013, 9:41 p.m. — EvaggelosBalaskas
Loop over the items in the current directory, and use Bash built-in case modification expansion to convert to lower case.
The case modification extension is available since Bash 4.
$ paste <(ls) <(ls | tr A-Z a-z) | while read OLD NEW; do echo mv -v $OLD $NEW; done
Aug. 5, 2011, 8:57 p.m. — Janos
<(cmd)
cmd
paste
... | tr abc ABC
while read old new; do ...; done
$old
$new