sort
1. Sort by field with # as delimiter
sort -t '#' -k2
2. The impact of locales on sorting
Using sort with the system default locale
~$ sort /tmp/buf
_Emacs
Emacs
%linux
Linux
vi(m)
Vim
Using sort with LC_COLLATE=C will sort lines by ASCII order, % value is 37, E is 69 etc
~$ LC_COLLATE=C sort /tmp/buf %linux Emacs Linux Vim _Emacs vi(m)