On Wed, Jun 19, 2013 at 06:12:57PM -0500, Dan Douglas wrote: > Thanks to mksh, posh, etc not supporting POSIX character classes at all, I'm > not so sure it's actually better in practice. (talking about standard shell > pattern matching of course)
I'm fairly sure nobody on the entire planet uses those shells except their authors and you. Now, since this is a bash mailing list, it's reasonable to talk about bash. If you're writing a script in bash, you MUST NOT use the [a-z] or [A-Z] ranges, or any other alphabetic ranges, unless you are working in the POSIX locale. If you use an alphabetic range in any other locale, you invite disaster. Here is disaster: imadev:~$ echo Hello World | tr A-Z a-z hÉMMÓ wÓSMÐ That is why you MUST NOT use alphabetic ranges in non-POSIX locales. Here's how you SHOULD do it: imadev:~$ echo Hello World | LANG=C tr A-Z a-z hello world imadev:~$ echo Hello World | tr '[:upper:]' '[:lower:]' hello world The latter is preferred if there is any chance you are working with non-ASCII letters, as it will handle them: imadev:~$ echo Ábc | tr '[:upper:]' '[:lower:]' ábc In the POSIX locale, Á isn't part of A-Z, so it is not matched: imadev:~$ echo Ábc | LANG=C tr A-Z a-z Ábc
