The previous tr example might not be right.
Code:
#!/bin/bash
for file in *.txt; do
tr '[[:lower:]]' '[[:upper:]]' <"$file" >"${file}.new"
mv "${file}.new "${file}"
done
The wild card may not match the pattern of files you want, but you can easily change that.
I don't use the ksh and don't know how variables are evaluated. But I'm not doing anything
fancy here so it should work for you.
I'm simply looping through every file, converting to uppercase
and saving the file with ".new" appended to them. Then I copy over the original
with the "mv" command. Redirecting the output to the same filename as the input would
cause the file to be zeroed before tr opens it.