Dear GNU,

Not sure if this is bug. But I think first one is legal command that is logically similar to second which works

Thank you,

Raj.

#1-- Error
[raj@rajvista ~]$ echo "Raj" | tr "[[:alpha:]]" "[[:lower:]]"
tr: misaligned [:upper:] and/or [:lower:] construct

#2--Ok

[raj@rajvista ~]$ echo "Raj" | tr "[[:upper:]]" "[[:lower:]]"
raj
[raj@rajvista ~]$

[raj@rajvista ~]$ tr --version
tr (GNU coreutils) 6.12
Copyright (C) 2008 Free Software Foundation, Inc.
License GPLv3+: GNU GPL version 3 or later <http://gnu.org/licenses/gpl.html>
This is free software: you are free to change and redistribute it.
There is NO WARRANTY, to the extent permitted by law.

Written by Jim Meyering.